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eGUIDE
CHEMISTRY
SLE – Section B
Semester - 2
SKV Institute
Self Learning Exercise – GSEB – Sem - 2
Chapter
Page
1. Chemical Bonding & Molecular Structures
3
2. States of Matter
8
3. Thermodynamics
12
4. Chemical Equilibrium
17
5. Some p-Block Elements
24
6. Hydrocarbons
28
7. Environmental Chemistry
34
SKV Institute of Chemistry
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SKV Institute – Ahmedabad
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2
Very Short Questions
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
UNIT – 1
SECTION B
1 Write octet rule.
 Kossel and Lewis in 1916 developed an important theory of chemical combination between
atoms known as electronic theory of chemical bonding. According to this - atoms can combine
either by transfer of valence electrons from one atom to another (gaining or losing) or by sharing
of valence electrons in order to have an octet in their valence shells. This is known as octet rule.
2 Define: Ionic bond:
 The bond formed by the combination of atoms having less ionization enthalpy combine with
atoms having more electro negativity is called ionic bond.
3 What is electrovalency?
 The bond formed by electrostatic attraction between positive ion and negative ion is called
electrovalency.
4 Write down factors affecting ionic bond formation.
 On the basis of approach of Kossel and Lewis, the formation of ionic bond depends on the
following factors:
1) Easy availability of positive ion and negative ion from neutral atoms.
2) Arrangement of positive ion and negative ion in ionic bond.
5 What is lattice structure?
 In the crystal structure of ionic compounds, there is regular three dimensional arrangements of
positive ions and negative ions. They are also combined with each other by Coulombic attraction
forces. Such an arrangement or structure is also called crystal structure.
6 What is lattice enthalpy?
 The energy required to remove gaseous form of ions to infinite distance from ionic compound in
one mole solid state is called lattice enthalphy.
7 Define: Covalent bond
 When two or more atoms of any elements attain octet structure by joint sharing of their valence
electrons the bond formed is called covalent bond.
8 Mention Lewis structure of N2 and CO2.

9 What is bonding pair of electrons and non-bonding pair of electrons?
 The electrons which takes part in sharing in the formation of chemical bond is called bonding
pair of electrons
 The electron pair which does not take part in the formation of bond does not take part in the
formation of bond is called non-bonding pair of electrons or lone pair of electrons.
10 Which molecule do not obey octet rule?
 BeCl2, PCL5.
11 What is polar and non-polar covalent bond?
 When a covalent bond is formed by atoms of element having different electro-positivity or
electro-negativity, the bond is called polar covalent bond. E.g. HCl
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Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
 When a covalent bond is formed by sharing of electrons of atoms of the same element, the bond
is called non-polar covalent bond. E.g. H2, Cl2 etc.
12 What is coordinate covalent bond?
 When a pair of electron is donated by the atom of only one from the two elements, the covalent
bond formed is called co-ordinate covalent bond. this bond is shown by the sign of an arrow (→)
and the direction of arrow is from the atom donating the electron pair to the atom receiving
electron pair.
13 What is bond length?
 The balanced distance between the nuclei of two atoms combined by bond in the molecule is
called bond length.
14 By which method bond length is measured?
 The bond length is measured by X-ray diffraction and spectroscopic methods. It is expressed in
picometer (pm = 10-12 m)
Lower value of bond length indicates higher stability.
15 What is bond angle?
 The angle between the orbitals possessing bonding electron pairs around central atom of the
molecule/ion is called bond angle.
16 Define: Bond enthalphy
 The energy required for breaking 1 mole bond in one mole gaseous substance is called bond
energy or bond enthalpy.
17 What is bond order? Give relation of bond order with bond length
 The number of bonds between atoms present in molecule is called bond order.
1
Bond order α ────────
Bond Length
18 Mention names of different steps of Born-Haber cycle.
 (1) Sublimation
(2) Dissociation
(3) Ionization
(4) Electron gain
(5) Crystal lattice formation
19 Draw resonance structure of O3 molecule.
20 Mention hybridisation and shape of PCl5
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Self Learning Exercise – GSEB – Sem - 2
 hybridisation- sp3d & Shape- Trigonal bipyramidal.
Very Short Questions
21 Write an example of octahedral structure and bond angel in it.
 Compound Hybridization
Geometry
Bond Angle
3
2
sF6
sp d
Octahedral 900
22 What are the shapes of ClF3 and XeF4?
 ClF3 – T-shape
&
XeF4 – Square planar
23 How many number of bonding pair of electrons and non-bonding pair of electrons are in SO2?
 There 4 bonding pair and 1 non-bonding pair of electrons in SO2.
24 Which conclusion is derive from VSEPR principle?
Repulsion produced
between non-bonding
and non-bonding electron
pair
Repulsion produced
between non-bonding
pair of electron and
bonding pair of electron
Repulsion produced
between bonding pair
and bonding pair of
electrons
(Lp – Lp)
(Lp – Bp)
(Bp – Bp)
25 What is bond angle in NH3? Why?
 The bond angle in NH3 is1070. This non-bonding electron pair of nitrogen atom repels the two
bonding electron pairs around nitrogen according to VSEPR. As a result, both these electron
pairs are pushed inside and the bond angle decreases from 109o 28’ to 107o.
26 Why dipole moment of BeF2 is zero?
 In linear molecule like beryllium fluoride (BeF2) polarity of the same magnitude exists between
beryllium and each fluorine but in opposite directions. As a result polarity becomes zero and the
dipole moment becomes zero.
27 Which type of magnetic property O2 possesses according valance bond theory?
 Paramagnetic type of property O2 possesses according valence bond theory.
28 Due to which factors, the interaction forces arise as per valence bond theory.
 The attractive forces are produced because of following factors:
(i) The attractive forces are produced between nucleus of the atom itself and its own electron N A –
eA and NB – eB.
(ii) The attractive force produced by nucleus of one atom and electron of other atom N A – eB and NB
– eA.
29 The assumption of atomic orbital overlapping is applicable to which molecules?
 The assumptions of overlapping of atomic orbital are applicable similarly to the
homonuclear/heteronuclear diatomic molecules and polyatomic molecules.
30 What is σ-bond?
 This type of σ-bond is formed by the end to end overlap of bonding orbitals along the internuclear axis. This is called axial overlapping.
31 What is π-bond?
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Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
 In the formation of π bond the atomic orbitals overlap in such a way that their axes remain
parallel to each other and perpendicular to the inter-nuclear axis.
32 Draw diagram of overlapping of p-p atomic orbitals.
33 Which scientist proposed molecular orbital theory?
 The molecular orbital theory was first presented by Mulliken and Hund in 1932.
34 What is bonding and anti-bonding molecular orbital?
 The number of atomic orbitals that combine with each other is the same for molecular orbitals,
half the number of these molecular orbitals are called Bonding molecular Orbitals (BMO) and
remaining half number of molecular orbitals are called Anti-Bonding molecular Orbitals
(ABMO).
35 Write down electronic configuration of O2 molecule.
 O2 = (σ1s)2 (σ*1s)2 (σ2s)2 (σ*2s)2 (σ2pz)2 (π2px)2 = (π2py)2
(π*2px)1 = (π*2py)1
36 Mention bond order & magnetic property of N2.
 N2 = (σ1s)2 (σ*1s)2 (σ2s)2 (σ*2s)2 (π2px)2 = (π2py)2 (σ2pz)2
Bond Order
=
= ½ (10 – 4)
= 3 (three bond)
N ≡ N bond is there.
As all electrons are paired the molecule is diamagnetic.
37 Write down factors affecting on intermolecular attractive force.
 The inter molecular attractive forces depends on the following factors:
(1) Shape of molecule.
(2) Number of electrons in a molecule.
(3) Contact surface of the molecule.
(4) Average inter-molecular distance
38 Define: Hydrogen bond
 The attraction force produced between electronegative elements having non-bonding electron pair
with positively charged hydrogen atom is called hydrogen bond.
39 Why N2 is gaseous and P4 is solid?
 The total number of electrons in N2 is 2 x 14 = 28 and that in P4 is 4 x 15 = 60. As the number of
electrons in P4 is more than that of N2, the intermolecular force of attraction is higher in P4 than
N2. Hencce N2 is gaseous and P4 is solid
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Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
40 Mention types of hydrogen bond?
 There are two types of H-bonds
(i) Inter-molecular hydrogen bond
(ii) Intra-molecular hydrogen bond
41 What is metallic bond?
 The attraction between Kernels and delocalized electrons keep the atomic kernels together. This
attraction between kernels and delocalized electrons is called metallic bond.
42 Define Coordinate covalent bond
 Co-ordinate covalent bond is one type of covalent bond. In the formation of covalent bond the
atoms combining with bond give same number of electrons for sharing. But the electron
required for sharing are donated by atom of only one electron, the bond is called co-ordinate
covalent bond.
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Self Learning Exercise – GSEB – Sem - 2
UNIT – 2
Very Short Questions
Section B
1. On which factors van der Waal’s forces depend?
(i) Shape of molecule
(ii) No. of electrons present
(iii) Contact surface area of molecule.
2. State the types of van der Waal’s forces.
(i) Dispersion forces or London forces
(ii) Dipole-dipole forces
(iii) Dipole induced dipole force.
3. What is dispersion force?
 The force of attraction in atoms or molecules in which there is a temporary dispersion in
electron density that affects the electron density of nearby atom or molecules, this is known as
dispersion force.
4. What is dipole-dipole force?
 In HCl molecule the chlorine atom is more electronegative than hydrogen atom, so the chlorine
atom acquires partial negative charge and hydrogen atom acquires partial positive charge,
hence there is a dipolar interactive attraction between two HCl molecules and such attractive
forces are called dipole-dipole forces.
5. What is hydrogen bond enthalpy?
 10 to 100 KJmol-1.
6. What is called thermal energy?
 Thermal energy is the energy of a body arising from motion of its atoms or molecules.
 It is directly proportional to the temperature of the substance.
 It is the measure of average kinetic energy of the particles of the matter and is thus responsible
for movement of particles. This movement of particles is called thermal motion.
7. What is change in volume of water when 1000 bar pressure is applied at 298K temperature?
 Its volume decreases by 4%.
8. State Boyle’s law and give its mathematical equation.
 At constant temperature the pressure of a fixed amount of gas varies inversely with its volume.
 Mathematically Boyle’s law can be written as given below
Pα
P=Kx
where K is proportionality constant
and it depends on the temperature and amount of the gas
PV = K
9. State the relation between density and pressure.
 The relation is,
 “At constant temperature for a fixed amount of gas the density of a gas varies directly as its
pressure.
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Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
10. At constant temperature fixed amount of nitrogen gas is filled in 10 litre vessel having pressure 10
bar. If this gas is transferred to 20 litre vessel then what will be the pressure of gas?
 P1V1 = P2V2,
∴ (10)(10) = 20P2
∴ P2 = 5 bar.
11. What is absolute zero temperature?
 At – 273.15°C temperature when the volume of gas is believed to be zero, the temperature is
called absolute zero temperature.
12. State the Charle’s law.
 At constant pressure and for fixed amount of a gas the change in volume by increasing or
decreasing 1 °C temperature is 273 of the original volume of a gas.
13. At constant pressure and 300 K temperature, volume of a definite amount of gas is 5 litre. What will
be the change in temperature if the volume of gas is to be halved?

=
∴ T2 =
∴ T2 =
= 150 K
14. Under which conditions Gay-Lussac’s law can be applied?
 At constant volume for a fixed mass.
15. State the mathematical form of Gay-Lussac’s law.
 Gay-Lussac’s law is written mathematically as
P α T,
(constant volume of gas, fixed amount)
P = KT
=K
16. State the relation between volume of a gas and number of molecules of gas at constant temperature
and pressure?
 V = Kn,
V= volume n = no. of molecules.
17. What is molar volume?
 The volume of any gas at STP is known as molar volume.
18. What is the volume of 14 g of N2 gas at STP?
 11.2 litres.
19. What is the value of gas constant R in bar milli litre mole-1 kelvin-1 unit?
 8.314x10-5 bar 9illilitre mole-1k-1.
20. What are ideal gases?
 The gases which obey the ideal gas equation and gas laws at all temperatures and pressure are
called ideal gases.
21. What is compressibility factor?
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Self Learning Exercise – GSEB – Sem - 2

is called compressibility factor, which is indicated by Z.
Very Short Questions
22. What are positive and negative deviations?
 If Z > 1, always it is positive deviation. If Z<1it is negative deviation.
23. State the van der Waal’s equation.

 This equation is known as van der Waals equation where a and b are constant and they depend
on the characteristics of gas. The constant ‘a’ indicates the measurement of intermolecular
attractive forces which is free from effect of
temperature and pressure.
24. Which factor is independent of temperature and pressure in van der Waal’s equation?
 The constant ‘a’ which indicates the measurement of intermolecular attraction.
25. What is critical temperature?
 The maximum temperature at which the gas gets liquefied; known as critical temperature,(Tc).
26. What is called critical volume?
 At critical temperature and critical pressure, the volume occupied by 1 mole of gas is called
critical volume (Vc) and this state is called critical state.
27. Why H2 gas is first liquefied than He gas?
 In the mixture of two gases having different critical temperatures one gets liquefied faster
because on cooling the mixture, the gas starts liquefying whose critical temperature comes first
so the H2 gas starts liquefying first and at that time He gas is not liquefied.
28. State Dalton’s law of partial pressure.
 The total pressure exerted by the mixture of non-reactive gases is equal to the sum of the
partial pressures of individual gas.
29. State Graham’s law of gaseous diffusion.
 The rate of diffusion of various gases varies inversely proportional to the square root of their
densities.
30. What is average ratio of diffusion rate NH3 and HCl gases?
 The ratio of diffusion rates for NH3(g) and HCl(g) is about 1.46 + 0.01.
31. State the isotopes of Uranium? Which isotopes of uranium is useful in nuclear energy?
 235U & 238U
 235U is useful in nuclear energy.
32. What is surface tension?
 The molecules of a liquid on any hypothetical unit length line on free surface of liquid exerts
the force parallel to the surface and perpendicular to the molecules, the other side o the line is
called surface tension of liquid. Due to surface tension the drop is always spherical and the
water (liquid) rises in a capillary tube upto certain level (height).
33. Define: Visocity
 There is a viscosity between any two successive layers in a movement (conduction) as a result
there exists a touching friction resistance force on the contact surface, such internal resistance
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Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
force is called viscous force. The property of having such a force existing in the liquid is called
viscosity.
34. What is vapour pressure?
 The concentration of the molecules in vapour state becomes constant and the pressure exerted
by the vapour molecules is in equilibrium with its liquid called vapour pressure.
35. On which factors vapour pressure of gas depends?
 The vapour pressure depends on the nature of liquid. This means that it depends upon the
intermolecular attraction forces of the liquid molecules. Weaker the intermolecular attractive
force, higher is the vapour pressure. Higher the temperature of liquid more is the vapour
pressure.
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Self Learning Exercise – GSEB – Sem - 2
UNIT – 3
Very Short Questions
Section B
1. What is meant by thermodynamic?
 The study of changes in all forces of energy and transformations is called thermodynamics.
2. What is meant by chemical thermodynamics?
 The study of changes in energy associated with physical and chemical reaction.
3. What is system? Mention its types.
 An extremely small part of the universe which is separated from the remaining part of
universe
by
a
definite
boundary
and
on
which
we
note
the observations of the experiments carried out by external changes is called system.
 There are three types of system depending on the exchange of energy and matter between
system and surrounding.
(iii) Open system
(ii) Closed system
(iii) Isolated system
4. What is called an isolated system? Give an example.
 The system which is not able to exchange energy and matter on its own with surrounding is
called an isolated system.
 The hot tea poured in a thermos flask of good quality provides its example at a particular
moment, but after sometime, it provides the example of the closed system. Hence, it is
difficult to find an example of an absolute isolate system.
5. Write definition of isothermal process.
 The system which is not able to exchange energy and matter on its own with surrounding is
called an isolated system.
 In fact, formation of isolated system is not possible but the thermos flask of very good quality
is the example of isolated system. The hot tea poured in a thermos flask of good quality
provides its example at a particular moment, but after sometime, it provides the example of
the closed system. Hence, it is difficult to find an example of an absolute isolate system.
6. Mention extensive properties of the substance.
 Some properties of the substance depend on the quantity of the matter. These properties are
known as Extensive properties.
 The mass of a substance, volume, enthalpy of formation, entropy, free energy, elevation in
boiling points, depression in freezing point etc. are such type of properties. Generally, these
properties are expressed in the unit of per mole or mole-1.
7. Write intensive properties of the substance.
 The properties of the substances which do not depend upon the mass of the substance but
depend upon the structure of the compounds are known as intensive properties.
 The melting point of solid substance, density, boiling point of liquid, conductivity, refraction
etc. are such type of properties.
8. What is an adiabatic process?
 During the change in the system, if the system does not lose heat or does not receive heat,
then the process is called Adiabatic process.
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Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
9. In which system there is exchange of energy with its own with surrounding but the exchange of
matter on its own with surrounding is not possible?
 In closed system there is exchange of energy with its own with surrounding but the exchange
of matter on its own with surrounding is not possible.
10. Is potential energy of a substance, a state function? Why?
 It is a state function because it depends only on the states not the path chosen.
11. Give definition: Thermodynamical reversible process.
 If the state of a system changing with infinitesimal rate, then the difference in state function
values of system are very small. This type of process is known as thermodynamically
reversible process.
 In this type of process, the equilibrium is established between system and surrounding at
each microscopic level.
12. Write mathmetical definition of enthalpy.
 The
total
amount
of
energy
obtained
from
internal
energy
(U)
of substance and energy obtained by product of pressure (P) and volume (V) is called
enthalpy (H).
H = U + PV
13. The absolute measurement of enthalpy of a substance is not possible? Why?
 Enthalpy, H = U + PV, as the absolute value of internal energy can not be measured so the
absolute value of enthalpy cannot be measured.
14. Mention the importance of the zeroth law of thermodynamics.
 The temperature of his body is measured by a thermometer. The thermometer comes in
contact
with
the
body
of
that
person,
the
heat
from
human
body enters into the mercury of the thermometer and the volume of the mercury increases.
When the temperature of the body and the temperature of mercury become equal, the
increase in the volume of mercury stops. Hence, it can be said that the temperature of the
body and that of the mercury in the thermometer is the same. This condition (state) is
known as thermal equilibrium.
15. Mention the values of q for endothermic and exothermic reaction.
 q is (+) for endothermic reaction.
q is (-) for exothermic reaction.
16. What are the values of W when the work is done by the system and on the system?
 w is (-) if work is done by the system &
w is (+) work is done on the system.
17. When mechanical work is important?
 The system which possess gaseous state, mechanical work is important.
18. When will be ΔH < ΔU for any chemical reaction?
 When Δn(g) < 0 then ΔH < ΔU.
19. Write importance of first law of thermodynamics.
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Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
 By using the First law, bond Enthalpy, Enthalpy of formation of compound Enthalpy of
combustion, change in internal energies (ΔU) in reaction, change in enthalpy (ΔH) etc. can be
obtained.
 The first law is associated with thermo chemistry of chemical reaction. Hence, the study of
thermo chemistry is carried out on the basis of the First law.
20. Mention the limitation of first law of thermodynamics.
 It is not possible to know whether any chemical reaction will occur on its
own (Spontaneous).
 In addition, the reactants will be transformed to what proportion of products also cannot be
obtained from the First law of thermodynamics
21. What are Cp and Cv?
 The heat capacity (Cp) for the temperature change at constant pressure.
 The heat capacity (Cv) for temperature change at constant volume
22. Mention the relation between Cp and Cv .
 Cp – Cv = R
23. What is meant by molar thermal conductivity? Mention its unit.
 The quantity of heat required for increase of temperature of 1 mole substance by 1 °C is
called molar heat capacity.
 The unit of molar heat capacity is joule.kelvin-1.mole-1
24. What is meant by reaction enthalpy?
 When a chemical reaction occurs at constant pressure and constant temperature, the change
in heat is called enthalpy change ΔH or heat of reaction.
25. What is called the standard form of a compound?
 In scientific practice, 1 bar pressure and 298 K temperature are
considered as standard states. The element or compound whose solid, liquid or gaseous form
is stable at 1 bar pressure and 298 K temperature, it is called a standard state.
26. Mention the names of allotropes of carbon and sulphur in standard state.
 Carbon – Graphite and Diamond
 Sulphur- Rhombic and monoclinic
27. Mention the value of neutralization of enthalpy.
 The value of enthalpy of neutralization isH+(aq) + OH‾(aq) → H2O(l);
ΔH = -56 kJmole-1.
28. What is meant by enthalpy of formation?
 When one mole of compound is formed under standard conditions from elemental state of
constituent elements, thermal changes is called standard enthalpy of formation ΔfH°
29. Write Hess’s law of constant heat summation.
 “The total change in enthalpy in a chemical reaction is equal to the algebraic sum of the
changes in enthalpy occurring during different steps.”
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Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
30. Mention the importance of Hess’s law.
 The enthalpy of reactants and products are constant at constant pressure and constant
temperature. Hence, if the reaction occurs in one step or more steps even then the value of
enthalpy change remains constant.
31. What are the important characteristics of spontaneous reaction?
 Entropy of universe increases in a spontaneous reaction.
 Free energy of system decreases in a spontaneous reaction.
32. Write second law of thermodynamics.
 The Second law of thermodynamics explains in which direction, either the forward or the
reverse, the reaction will spontaneously occur. This law can be as mentioned below:
(i)
In all spontaneous processes, the entropy of the universe increases.
(ii)
The free energy of the system in all the spontaneous processes decreases.
33. Write formula of entropy change and its unit
 ΔS =
 Unit: cal/K or J/K
34. What will be the change in enthalpy[ENTROPY] of the system when 1 mole water is boiled at
373 K temperature and converted to vapour having the same temperature? (The molecular
enthalpy of vapourisation of water is 40.668 kilo Joule mole-1.
 ΔS =
=
35. Why the entropy of the system increases with increase in temperature?
 With the increase in temperature the translational motion as well as rotational motion and
vibrational motion increase and so there is increase in randomness at molecular level.
36. Mention the formula the change in entropy when ideal gas is expanded in vacuum.
 ∴ ΔS = R ln
= 2.303 R log
where, V1 = initial volume of gas
V2 = final volume of gas
37. Mention the relation among free energy change enthalpy change and entropy change.
 ΔG = ΔH – TΔS
where ΔH and ΔS are the values of change in enthalpy and change
in entropy.
38. The determination of absolute free energy of a substance is not possible. Why?
 The absolute value of free energy of any substance cannot be determined because it depends
on the absolute value of enthalpy of the substance.
39. Write definition: Standard free energy of formation of a compound.
 “The value of change in free energy in direct reaction when 1 mole compound is produced
from its elements in standard state will be equal to the value of change in standard free
energy of formation of the compound.”
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Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
40. At definite temperature there is change in volume when the pressure of ideal gas changes. Write
formula for change in free energy associated with it.
 ∴ ΔG = 2.303 Nrt ln
where n is the number of moles of the gas and V1 and V2 are the
volumes of the gas at initial and final state.
41. Suppose a reaction occurs on its own, then what could be value of equilibrium constant?
 For spontaneous reaction, ΔG° = negative (-ve), hence value of equilibrium constant K > 1
42. What can be the value of ΔG for a chemical reaction having equilibrium constant 4.2 x 10-2?
 ΔfG° = - 2.303 RT log K
∴ ΔfG° = - 2.303 RT log 4.2 x 10-2
= - 2.303 x 8.314 x 298 x (0.6233 -2)
= 7855.25 J/K
43. Mention the relation between change in free energy and standard potential of electro chemical
cell.
 ΔG° = -Nfe°cell
where E°cell is the difference of standard reduction
potentials of both the half cells of the complete cell.
44. Mention the limitation of second law of thermodynamic.
 This law is not able to give information about the rate of chemical reactions. Thus, the
thermodynamics is independent of chemical kinetics.
45. Write third law of thermodynamic.
 The third law of thermodynamics can be expressed as below :
 “The value of entropy of a completely pure crystalline substance is zero at
zero temperature”
absolute
46. What is molar entropy? Mention its unit.
 The entropy of one mole of a substance is called molar entropy and it is expressed as Sm.
 The entropy of one mole of a substance at constant temperature and standard state is called
standard molar entropy S°m.
 The unit of molar entropy is joule.kelvin-1.mole-1.
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Self Learning Exercise – GSEB – Sem - 2
UNIT – 4
Very Short Questions
Section B
1. What is meant by reversible reaction?
 The reaction in which both transformation of the reactant to product and product to reactant
occur is known as a reversible reaction.
2. What is called chemical equilibrium?
 The equilibrium established in chemical reactions is called chemical equilibrium. E.g.
Decomposition of calcium carbonate.
3. How can be said that equilibrium is dynamic in nature?
 The equilibrium is dynamic and not steady or static as the forward and the reverse reactions
occur with the same velocity at the equilibrium time in equilibrium reactions in closed vessels.
4. How many types of equilibrium are there? Which are they?
 There are two types of equilibrium. (1)Physical equilibrium (2) Chemical equilibrium.
5. What is called reverse reaction?
 The change of product to reactant is called the reverse reaction.
6. What is meant by homogeneous equilibrium? Give its example.
 If the reactants and products are in one similar phase, the equilibrium is called homogeneous
equilibrium.E.g. N2(g) + 3 H2(g) ⇌ 2 NH3(g)
7. What is meant by heterogeneous equilibrium? Give its example.
 If reactants and products possess more than one phase, the equilibrium is called
heterogeneous equilibrium. E.g. CaCO3(s) ⇌ CaO(s) + CO2(g)
8. Mention requirements for chemical equilibrium.
 Reaction must be reversible and taking place in a closed system.
 External factors like temperature, pressure and concentrations of components which can affect
the equilibrium must remain constant.
9. Mention the law of active masses.
 At a given temperature and pressure, the rate of a chemical reaction is proportional to the
product of the concentration in moles in proper power of the reactants.
10. Which scientist gave the law of mass action?
 Gouldberg and Waag gave the law of mass action.
11. Interpret Keq = Kc
 If at equilibrium the concentration of the reactants is expressed in terms of Mole/Litre [c] then
the equilibrium constant Keq = Kc.
12. Interpret Keq = Kp.
 If at equilibrium the concentration is expressed in terms of partial pressure then Keq = Kc.
13. Write formula of Kp for NH4COONH2(s) → 2NH31(g) + CO2(g).
 Kp = (PNH3)2 x PCO2.
14. Give the formula of equilibrium constant for decomposition of NH4HS(s).
 Kp = PNH3 x PH2S.
17
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
15. Write formula showing relation between Kc and Kp.

Kc x
where, Δn(g) = (c + d)-(a + b)
16. Give the law of equilibrium.
 Keq =
.This equation is known as law of equilibrium.
17. Mention the formula for equilibrium constant for the reaction 4NH3(g) + 5O2(g) ⇌ 4NO(g) + 6H2O(l).
 Kc = [NO]4 [H2O]6 / [NH3]4 [O2]5
18. Under which condition Kp and Kc will be equal?
 If Δn(g) for a reaction is zero then Kp and Kc will be equal.
19. When Kp > Kc?
 If Δn(g) for a reaction is +1 then Kp > Kc
20. Write Le-Chatelier’s principle.
 “If from the factors determining the equilibrium state, any one factor is changed, there will be
such a change in the system that the effect will be nullified or made negligible so that the value
of equilibrium constant at that temperature will remain constant.”
21. What idea can be obtained by Le-Chatelier’s principle?
 If the changes in the factors affecting the equilibrium occur then the system will try nullify the
effect .
22. Why concentrations of components remain constant at equilibrium?
 The concentration of components remain constant because at equilibrium the rate of forward
reaction is equal to the rate of reverse reaction.
23. Which are the factors affecting equilibrium?
 Factors affecting the state of equilibrium are as follows:
(i) Concentration of reactants and products
(iii) Temperature
(ii) Pressure
(iv) Catlyst
24. Give equation showing relation between ΔG and Qc.
 ΔG = ΔG° + RTln Qc.
25. Give unit for the equilibrium constant of the reaction N2(g) + 3H2(g) ⇌2NH3(g).
 The unit of equilibrium constant will be (atm)-2
26. If Qc < Kc and Qc > Kc then in which directions the reaction will occur?
 If Qc < Kc then the reactions occurs in the forward direction and if Qc > Kc then the reaction
occurs in the reverse reaction.
27. Give formula of Kc for the reaction Ag2O(s) + 2HNO3(aq) ⇌ 2AgNO3(aq) + H2O(l).
 Kc = [AgNO3]2 / [HNO3]2
28. Write relation between ΔG0 and equilibrium constant K.
 ΔG0 = -RTln K
29. What will be the effect of catalyst on equilibrium?
18
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
 There is no effect of catalyst on the equilibrium constant and so the proportions of products
remain same but the rate of reaction to attain equilibrium increases.
30. In the reaction A2 + B2 ⇌ 2AB + Q cal, what should be decreased to increase the proportion of AB?
 The rate of reverse reaction should be decreased in order to increase the proportion of AB.
31. Mention the function of catalyst.
 The main function of the catalyst is to increase the rate of reaction.
32. Complete the reaction
Fe3+(aq)
+
SCN-(aq) ⇌
Light yellow colour Colourless
 Fe3+(aq)
+
SCN-(aq) ⇌ [Fe(SCN)]2+(aq)
Light yellow colour Colourless
33. In how many sections, Michael Faraday classified substance?
 Michael Faraday classified substances in two sections ;
(i) Electrolytes and (ii) Non-electrolytes.
34. What is called an electrolyte? Give example.
 Those substance which conducts electric current in their aqueous solutions are called
electrolytes. E.g Solution of sodium chloride.
35. What is called a non electrolyte? Give example.
 Those substance which do not conduct electric current in their aqueous solutions are called nonelectrolytes. E.g Pure water.
36. What is called a strong electrolyte? Give example.
 The electrolytes which ionize completely on dissolution are strong electrolytes.
37. What is called dissociation?
 The process in which the molecules of sodium chloride gets converted to sodium ions and
chloride ions is known as dissociation.
38. What is called ionization?
 The process by which free ions are formed by dissociation is known as ionization.
39. Approximately how many litres of HCl is secreted in the stomach of human being?
 300 mL/day
40. Which acid is included in vinegar?
 Acetic acid is included in vinegar.
41. What can be called acid and base according to Arrhenium theory?
 According to Arrhenius concept, substance which dissociate in water and give hydrogen ion
(H+) are called acids and substance which dissociate in water and give hydroxyl ion (OH‾) are
called bases.
42. Mention two drawbacks of Arrhenium theory.
 Proton (H+) is highly unstable.
 It cannot exist independently
19
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
43. Give definitions of acid-base according to Lowry-Bronsted theory.
 The substance which gives a proton or donates a proton is called the acid and the substance
which receives a proton or accepts a proton is called the base.
44. Give definitions of Lewis acid-base.
 A substance which can accept a pair of electrons is an acid and a substance which can donate
an electron pair is called a base
45. Which substances do not obey the definition of Lewis acid-base?
 BeCl2 and PCl5 do not obey the definition of Lewis acid-base.
46. What is used to measure strength of different acid-base according to Lowry-Bronsted theory.
 The number of protons donated or accepted is used to measure the strength.
47. Write conjugate acids of water and dimethyl amine.
 Conjugate acid of water is H3O+ and of dimethyl amine is CH3NH3+.
48. What will be the conjugate acid of (C6H5)2NH?
 (C6H5)2NH2+
49. Write conjugate acid-base of H2PO-4.
 Conjugate acid:
H3PO4
Conjugate base:
HPO4-2
50. Give definition of conjugate base.
 Every acid on losing an electron forms a conjugate base.
51. Give definition of conjugate acid.
 Every base on accepting a proton will form a conjugate acid.
52. What indicates the value of Ka and Kb?
 The values of Ka and Kb indicate the dissociation constant of acid and dissociation constant of
base reaspectively.
53. CH3NH2 is stronger base in comparison to NH3. Why?
 Due to higher value of ionization constant, CH3NH2 is stronger base in comparison to NH3.
54. Which substance acts as Lewis acid-base?
 A substance which can accept a pair of electrons is an acid and a substance which can donate
an electron pair is called a base
55. Classify the given substances in Lewis acid-base:
AlCl3, BF3, CH3CH2OH, NH3, NH2-, Ag+..
 AlCl3, BF3, Ag+ are Lewis acid and CH3CH2OH, NH3, NH2- are Lewis base.
56. What is meant by self ionization of water?
 H2 O + H2 O ⇌ H3O+ + OH The dissociation of water into hydronium ion and hydroxyl ion is known as self ionization of
water.
57. What is meant by ionic product of water?

. This is known as ionic product of water.
20
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
58. What is concentration of pure water at 298K temperature?
 [H2O] = 55.55 M is the concentration of pure water at 298 K temperature.
59. Give definition of Ph.
 Ph of a solution is the negative logarithm to the base 10, of the concentration of hydrogen or
hydronium ion.
∴ Ph = -log10[H3O+].
60. Give definition of Poh.
 Poh of a solution is the negative logarithm to the base 10, of the concentration of hydroxyl ion.
∴ Poh = -log10[OH-].
61. What will be the sum of values Ph and Poh at 298 K temperature?
 Ph + Poh = 14.
62. On the basis of which values of Ph, solutions can be said to be acidic, basic or neutral?
 pH < 7
Acidic solution
pH > 7
Basic solution
pH = 7
Neutral solution
63. What is the Ph of CH3COONa solution?
 The Ph of CH3COONa is more than 7.
64. What is the Ph of FeCl3 solution?
 The Ph of FeCl3 solution is less than 7.
65. What will be the effect of aqueous CaCl2 solution on litmus paper?
 Aqueous solution of CaCl2 will turn red litmus paper blue.
66. What is meant by hydrolysis of salt?
 Salt is obtained by combination of acid and base in definite proportion. When the salt is
dissolved in water, ionisation occurs, this is known as hydrolysis of salts.
67. Which instrument is used to determine accurate Ph of solution?
 Ph can be determined with the help of instrument called Ph meter.
68. What is meant by hydrolysis constant?
 Hydrolysis reaction is an equilibrium reaction and so its corresponding equilibrium constant can
be calculated which is known as hydrolysis constant (Kh).
69. What is called a buffer solution?
 The solution which resists the change in Ph carried out by addition of acid or base in small
proportion to them or are being diluted, and the values of their Ph remain
constant are called buffer solutions.
70. Give one example of each of acidic, basic and neutral buffer solutions.
 Acidic – CH3COOH + CH3COONa; Ph < 7;
Basic – NH4OH + NH4Cl;
Ph > 7;
Neutral – CH3COOH + NH4OH;
Ph ≈ 7.
21
Self Learning Exercise – GSEB – Sem - 2
71. Give examples of sparingly soluble salts.
 AgCI, BaSO4, PbSO4 are sparingly soluble salts.
Very Short Questions
72. Give definition of solubility product (Ksp).
 The solubility product (Ksp) is the multiplication of the concentrations of products formed in the
reaction.
73. In which solvent, nonpolar substance like naphthalehe dissolves?
 Naphthalene can dissolve in non-polar solvent like benzene
74. Give formula for solubility product (Ksp) of sparingly soluble salt Sb2S3.
 Sb2S3 ⇌ 2Sb+3 + 3S-2
Ksp = [Sb+3]2 [S-2]3
75. Mention the condition between Ip and Ksp.
 (i) Ip > Ksp,
Precipitates of sparingly soluble salt will be obtained or
precipitation will occur.
(ii) IP < Ksp
Precipitates of sparingly soluble salt will not be obtained or
precipitation will not: occur.
(iii) IP = Ksp
Shows equilibrium, hence precipitation will not occur but
solution will remain in saturated state.
76. Give four examples of sparingly soluble salt.
 AgCI, BaSO4, PbSO4 and H2S are sparingly soluble salts.
77. What is indicated by value of Ksp of sparingly soluble salt?
 The solubility product constant is indicated by the value of Ksp of sparingly soluble salts.
78. What is not included in the equation of Ksp equilibrium constant of a sparingly soluble salt?
 The initial concentration of salt is not included in the equation of Ksp.
79. What is called common ion effect?
 The sparingly soluble salt that has dissolved in solution that is completely dissociated and so it
is in ionic form. Hence, it is a strong electrolyte. Solubility product is ionic equilibrium and its
equilibrium constant will depend on temperature, but its value will be constant at constant
temperature.
 On adding soluble ionic substance like KCI in the solution of a sparing soluble salt like AgCI
AgCI(s) ⇌ Ag+(aq) + Cl‾(aq)
KCI(s) → K+(aq) + CI‾(aq)
 The Cl‾ from AgCI in equilibrium and CI‾ ion obtained by complete ionisation of K CI, the
concentration of Cl- will increase. Hence, according to Le Chatelier’s principle, the equilibrium
will shift towards left side so as to nullify the effect of Cl- i.e. more AgCI will be formed. In other
words, there will be decrease in solubility of AgCI. Hence, due to effect of common ion on
sparingly soluble salt its solubility decreases and sparingly soluble salt precipitates more.
 This is known as common ion effect.
80. The ion of which group are not precipitated in presence of NH4OH and NH4Cl in qualitative analysis.
 The ions of group III B are not precipitated in presence of NH4OH and NH4Cl in qualitative
analysis.
81. The ions of which group are precipitated in presence of HCl and H2S in qualitative analysis.
22
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
 The ions of group III A are precipitated in presence of HCl and H2S in qualitative analysis.
82. What is meant by ionic product Ip?
 A product of concentration of ions in an aqueous solution at any time is called ionic product of
salt.
83. How can acidic buffer solution be prepared? Give example.
 Acidic buffer solution can be prepared by mixture of weak acid and its salt with strong base. For
e.g.
CH3COOH + CH3COONa; Ph < 7
84. How can basis buffer solution be prepared? Give example.
 Basic buffer solution can be prepared by mixture of weak base and its salt with strong acid. For
e.g.
NH4OH + NH4Cl;
Ph > 7
85. Mention the importance of solution.
 Solution always forms electrons which helps conducting electricity.
86. How can neutral buffer solution be prepared?
 Neutral buffer solution can be prepared by neutralisation of weak acid and weak base. For e.g.
CH3COOH + NH4OH;
Ph ≈ 7
23
Self Learning Exercise – GSEB – Sem - 2
UNIT – 5
Very Short Questions
Section B
1. Why there is variation in physical and chemical properties of p-block elements?
 The valence shell electron configuration of elements of p-block is ns2 np1 to ns2 np6. Besides
there is difference in the electronic configuration of inner orbitals, as a result of which there is
variation in physical and chemical properties of p-block elements.
2. What is called inert effect?
 On moving down the group from 13 to 16 the oxidation state which is two units less than the
highest oxidation state becomes more stable. This trend is called inert pair effect.
3. Write the name of ores of boron.
 Borax, Kernite, Colemanite, Orthboric acid.
4. State the main ores of aluminium.
 Bauxite, Orthoclase, Cryolite, Corundum, Beryl, Mica.
5. State the order if ionization enthalpy of boron group elements.
 B>Al>Ga>In>Tl.
6. Why boron has tendency to form covalent bond?
 Due to its small size and high ionization energy, boron has tendency to form covalent bond.
7. Which oxidation state of boron group is most stable as we go down?
 (+3) for boron and aluminium & (+1) for Ga, In, Tl.
8. State the preparation of boron hydride.
 Boron hydride is obtained by reaction of BF3 with LiH.
450 K
2BF3 + 6LiH ——→ B2H6 + 6LiH
9. Write the molecular formula of borane.
 BnHn+4 and BnHn+6
10. Give the molecular formula of tetrahydraluminate (III)
 The molecular formula of tetrahydraluminate(III) is Al(OH)4.
11. Draw the dimeric structure of AlCl3.
12. Why BF3 and AlCl3 are used as catalyst in aromatic substitution reaction?
 BF3and AlCl3 arw strong Lewis acids and therefore used as a catalyst in Friedel and Crafts
alkylation reaction and electrophilic aromatic substitution reaction.
13. Oxide of which element of boron group is strong base?
 Thallium oxide is strong base.
24
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
14. State empirical formula of alum.
 K.Al.(SO4)2.12H2O is the empirical formula of alum.
15. State the uses of alum.
 To convert hard water to soft water and as a mordant in chemicals of colour dye.
16. State the isotopes of boron.
 Boron has two isotopes 10B and 11B.
17. Which are the allotropes of boron?
 The two allotropes of boron are amorphous form in dark brown colour and crystalline form in
black metallic luster.
18. State the reaction of boron with concentrated HNO3.
 B + 3HNO3
H3BO3 + 3NO2
19. What is obtained by reaction of boron with KOH?
 2B + 6KOH(l)
2K3BO3 + 3H2
Potassium borate
20. State the chemical reaction to prepare boric cid from borax.
 Acidifying the aqueous solution of borax by adding HCl or H2SO4, Boric acid is obtained which on
concentration and cooling gives crystals of boric acid.
Na2B4O7 + 2HCl + 5H2O
4H3BO3 + 2NaCl
Na2B4O7 + H2SO4 + 5H2O
21. State the three forms of borax.
 Borax is found in three forms.
(a) Prismatic:
(b) Octahedral:
(c) Borax glass:
4H3BO3 + Na2SO4
Na2B4O7.10H20
Na2B407. 5H20
Na2B4O7
22. What is called borax bead?
 On heating borax, due to its decomposition swells and loses wate of crystallization and becomes
anhydrous; on further heating it melts and forms glassy, transparent bead known as borax bead.
23. Which colour are obtained when borax bead is heated with Ni2+, Co2+, Cr3+, Cu2+ and Mn2+?
 When the glassy, transparent bead is dipped in coloured ions like Ni2+, Co2+, Cr3+, Cu2+, Mn2+ and
heated, they are converted into their metaborates respectively and they are coloured and their
colours are brown, blue, green and pink respectively.
24. Which product are obtained by hydrolysis of boron compounds?
 On hydrolysis of BC13 and BN, they give boric acid.
BCl3 + 3H20
BN + 3H2O
H3B03 + 3HCl
H3BO3 + NH3
25. What is obtained when boric acid reacts with ethanol in pressure of H2SO4?
25
Self Learning Exercise – GSEB – Sem - 2
 In presence of H2SO4 it reacts with ethanol and form ethyl borate.
H3BO3 + 3C2H5OH
Ethyl borate
Very Short Questions
B(OC2H5)3 + 3H2O
26. State the two uses of boric acid?
 In food industry it is used as a preservative for the preservation of food.
 Used in the preparation of pigments and borax.
 It is used (in medicine) as an eye wash.
 Used in the manufacturing of enamels and pottery glazes
27. What is inorganic benzene?
 At 450 K temperature, if diborane is heated with NH3, forms Borazine having structure like
benzene and hence it is also called inorganic benzene.
28. State the reactions of aluminium with H2SO4 and NaOH
(i)
(ii)
2Al + 6H2SO4
Al2(SO4)
2Al + 2NaOH + 6H2O → 2Na[Al(OH)4] + 3H2.
29. Why carbon has catenation property?
 The atomic size of carbon is less and electronegativity is higher, further the C-C bond enthalpy is
also very high so it indicates maximum catenation property.
30. State the ores of lead.
 Galena (PbS) is the principal ore of lead found along with zinc blende (ZnS). Other ores of lead
are anglesite (PbSO4) and cerussite (PbCO3).
31. State the order of stability of dihalides of carbon group.
 The stability of dihalides increases in order CX2 < < SiX2 < < GeX2 < < SnX2 < PbX2
32. Write uses of quartz.
 Quartz is used as a piezoelectric crystal, crystal oscillator and in transducers.
33. How silica gel is prepared?
 Silica gel is obtained by acidification of sodium silicate.
34. State the uses of silica gel.
 When silica gel is dehydrated, the obtained silica gel is extensively used in chromatography and
for the drying of other substances, and therefore, it acts as a drying agent
35. Give the uses of SnO2.
 SnO2 is used in polishing powder and in manufacturing of glass and pottery.
36. Complete the reaction Pb3O4 + 4HNO3
 Pb3O4 + 4HNO3 → 2Pb(NO3)2 + PbO2 + 2H2O
37. What happen when tin oxalate is heated?
 SnO is obtained by heating tin oxalate.
SnC2O4 → SnO + CO + CO2
38. State the amourphous form of carbon.
26
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
 Coal wood charcoal, animal charcoal lamp black, coke, gas carbon etc are amorphous allotropes
of carbon.
39. Why diamond is very hard?
 All the carbon atoms are bound to each other by covalent bonding and these bonds are very
strong. So diamond is extremely hard solid substance.
40. Why graphite is soft?
 According to the circumstances there might be a little change possible between the two layers.
Due to weak van der Waals forces the graphite is soft.
41. State the preparation of acetylene and beryllium carbide.
 Acetylene –
2C + H2 → C2H2
 Beryllium carbide – 2Be + C → Be2C
42. Write the reactions of carbon with HNO3 and H2SO4.
(i)
C + con. 4HNO3 → CO2 +4NO2 + 2H2O
(ii) C + 2H2SO4 → CO2 + 2SO2 + 2H2O
12C + 9H2SO4 → C6(COOH)6 6H2O + 9SO2
43. What is Freon? Give its uses.
 CF2Cl2, which is known as Freon, was used in refrigerator as a coolant.
44. State the uses if carborandum.
 It is use as refractoy and abrasive for sharpening and grinding metals and other substances.
45. Which are carbonyl complex of Fe and Ni?
 The carbonyk compounds of Fe is [Fe(CO)5] and that of Ni is [Ni(CO)4].
46. For which mond carbonyl process is used?
 Mond's carbonyl process is used to obtain pure nickel metal from impure nickel metal by
forming tetra carbonyl nickel.
47. What is dry ice?
 When liquid CO2 allowed to evaporate rapidly i.e.expands rapidly, it is converted into solid
which is known as dry ice.
48. State the general formula if silane.
 The general formula of silane is SinH2n+2.
49. Which is bond linkage and repeating unit in silicones?
 Silicones are synthetic materials containing Si - O - Si bond linkage. These compounds are
polymeric
substances
containing
R2SiO
repeating
unit.
They
have
general formula (R2SiO ), where R is methyl or phenyl group.
50. Which ions are present in aluminosilicates?
 SiO44- and AlO45-.
51. State the uses of ZSM-5.
 ZSM-5 is used in petrochemicals. It converts alcohol directly into gasoline (petrol) by
dehydratiosn and the mixture of hydrocarbons is formed.
27
Self Learning Exercise – GSEB – Sem - 2
UNIT – 6
Very Short Questions
Section B
1. Which are main natural sources of hydrocarbons?
 The main natural sources of hydrocarbons are petroleum, natural gas, coal etc.
2. Write down types and general molecular formula of alkene hydrocarbons.
 There are two types of alkene hydrocarbons. Acyclic – CnH2n and Cyclic – CnH2n-2.
3. Draw structure of saturated hydrocarbon with molecular formula C3H6 and also mention
hybridization and type of each carbon in it.
 CH2=CHCH3, Her the fisrt two carbon atoms are sp2 hybrid and third carbon is sp3 hybrid.
4. Why quarternary hydrogen in hydrocarbon doesnot exist?
 In a quaternary (4o) carbon the four carbons complete its tetra-valency, and hence, no hydrogen
can be attached to it. As a result, quaternary (4o) hydrogen is not possible.
5. Write down possible structural formula and IUPAC name of a compound containing C3H4 molecular
formula.
 CH≡C-CH3 Propyne
6. Write down structural formula and IUPAC name of neopentane.
Compound
IUPAC name
Structural formula
Neopentane
2, 2 Dimethyl propane
7. Write down two equations to prepare saturated hydrocarbon from unsaturated hydrocarbon.
CH2=CH2 + H2
Ethene
CH3-C≡CH + 2H2
Propene
CH3 - CH3
Ethane
CH3CH2CH3
Propane
8. Write down equation for preparation of propane from 2-Chloropropane.
CH3CH2(Cl)CH2 + H2
CH3CH2CH3 + HCl
2-Chloro propane
Propane
9. Which sodium salt of carboxylic acid is required to prepare propane? Write down the equation to
prepare propane.
 CH3CH2COONa
Sodium propanoate
28
CH3CH2COOH
CH3CH2COONa
Propanoic acid
Sodium propanoate
Self Learning Exercise – GSEB – Sem - 2
CH3CH2COONa
Sodium propanoate
Δ
Very Short Questions
CH3CH3 + Na2 CO3
Ethane
Sodium carbonate
10. Which type of attraction forces are formed between molecules of alkane compound? Why?
 Due to non-polar character, alkane compounds create weak intermolecular attraction (van der
Waals force) between two molecules.
11. Write down different physical states of alkanes carrying different number of carbons.
 Because of the weak intermolecular attraction forces in alkane, C1 to C4 carbon containing alkane
compounds are in gaseous form. C5 to C17 carbon containing alkanes compounds are in liquid
form and alkanes containing C18 or more carbon atoms are in solid form at normal temperature
(298 K).
12. Why alkanes are insoluble in water?
 Due to non-polar nature alkanes are insoluble in polar solvent like water.
13. Why boiling point of propane is higher than ethane?
 The intermolecular attraction forces increase with increase in carbon atom in the alkane series.
It is observed that alkanes having high molecular weights possess high boiling point.
14. What effect the branching of an alkane has on its boiling point?
 As the branching increases, there occurs a decrease in the contact surface area. Due to the
decrease in contact surface area intermolecular forces decrease. Thus, less amount of energy is
required to convert liquid into vapour state.
15. Among n-pentane and neopentne, whose boilng point is higher? Why?
 n-pentane will have higher boiling point than neo pentane, The reason for decrease in the
boiling points from primary (1o) to tertiary (3o) can be given as under. As the branching
increases, there occurs a decrease in the contact surface area. Due to the decrease in contact
surface area intermolecular forces decrease. Thus, less amount of energy is required to convert
liquid into vapour state.
16. Write down equation for cyclisation (or dehydrogenation) of hexane.
17. How reaction of alkane with vapour of water is industrially important?
 Reaction of alkane in presence of Ni catalyst with water vapour at higher temperature,
dihydrogen gas is released. This process is used in industries to obtain dihydrogen gas.
18. Write IUPAC name of CH3(CH2)4 – CH – (CH2)3 – CH3
│
CH2 – CH(CH3)2
 5 (2 Methyl propyl) nonane
19. Write IUPAC name of
29
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
 Deca-1,3,5,9-tetraene
20. What is ''Lindlar's catalyst"? What is its use?
 The mixture of palladium and charcoal is known as Lindlar’s catalyst.
 It is used in the hydrogenation reaction of alkynes to form alkene.
21. Write down an equation for preparation of alkene by dehalogenation.
22. What is acidic dehydration of alcohol?
 Alkene is obtained by reacting alcohol with conc. H2SO4 at 443 K temperature. During
this
process water molecule is released. This process is called dehydration. It is also known as
acidic dehydration. It is also known as acidic dehydration of alcohols.
CH3CH2OH
CH2CH2 + H2O
Ethanol
Ethene
23. What number of carbon atoms containing alkene are generally in liquid form and gaseous form?
 Alkene containing two, three or four carbon atoms are in gaseous form, C5 to C18 members are in
liquid form and those with more number of carbons are obtained in solid form.
24. Why boiling point of 2-methyl prop-l-ene is less than but-1-ene?
 The boiling points of isomers having linear chain are higher than those of alkenes having
branched chain.
 Hence, boiling point of 2-methyl prop-l-ene is less than but-1-ene
25. What are symmetrical and unsymmetrical alkenes?
 If the number of hydrogen atoms connected to carbon atoms of the ethylenic double bond are same, it is called
symmetric alkene and if they are different than it is called unsymmetric alkenes.
26. Write down Markovnikov’s rule.
 "In the addition reaction of compounds having asymmetric ethylinic double bond the
electronegative part of asymmetric reagent attaches with the ethylinic carbon having less
number of hydrogens."
27. Write down reaction of but- I ene with HBr.
 CH3CH2CH=CH2
But – 1 ene
CH3CH2CH(Br)CH3
2 Bromo butane
28. Write down reaction: Propene+ HBr benzoylperoxide
30
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
29. Write IUPAC name of the products obtained by addition reaction of HBr to pent-I-ene
(i) in the absence of peroxide and (ii) in the presence of peroxide
 2 Bromo pentane and 1 Bromo pentane
30. Write down IUPAC names of isomers of alkyne having C4H6 formula
Molecular formula
C4H6
Structural formula (Isomer) IUPAC name
CH3-CH2-C≡CH
But-1-yne
Ch3-C≡C-CH3
But-2-yne
31. Write down IUPAC names of chain isomers of alkyne having C5H8 formula.
Molecular formula
C5H8
Structural formula (Isomer)
CH≡C-CH2-CH2-CH3
CH3-C≡C-CH2-CH3
CH3-CH-C≡CH
│
CH3
IUPAC name
Pent-1-yne
Pent-2-yne
3 Methyl but-1-yne
32. Give examples of reaction of alkynyl halide with sodamide.
33. Which alkene and alkyne have specific smell ?
 Ethene and ethyne
34. Which alkynes are gaseous at normal temperature?
 The first three members of alkyne series are in gaseous form
35. Which reactions of ethyne are showing its acidic nature?
CH≡CH + Na → HC≡C‾ Na+ + ½ H2
Ethyne
Mono sodium ethanide
CH≡CH + NaNH2 → HC≡C‾Na+ + NH3
Ethyne
Mono sodium ethanide
36. Draw structure of naphthacene and phenanthrene.
31
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
37. Who discovered benzene first and from which he got benzene?
 Scientist Michael Faraday for the first-time obtained benzene from illuminating gases, in 1825.
38. Which information is obtained by addition reaction of benzene?
 By addition reaction of benzene it can be proved that benzene contains
hexagonal cyclic structure
and in the ring three single bond between C - C and three double bond between C = C are
present.
39. Why only one isomer is possible of monosubstituted benzene?
 Only one isomer is possible of monosubstituted benzene because 6 carbons and 6 hydrogen of benzene
are equivalent in position and in reactivity.
40. Draw electronic structures of benzene proposed by Lewis.
41. Which two physical properties give support to resonance structures of benzene?
 The study of bond length and resonance energy.
42. How resonance energy of benzene is decided?
 Resonating structures of benzene can be further proved by their resonating energy. Cyclo
hexene, containing one double bond has hydrogenation enthalphy 119.66 KJmol-1. Therefore,
benzene having three double bonds should have hydrogenation enthalpy of 119.66 x 3 = 358.9
KJmol-1. But the experimental hydrogenation enthalpy of benzene is 208.36 KJmol-1. Thus,
benzene has 358.9 - 208.36 = 150.63 KJmol-1 enthalpy less. The amount of heat of
hydrogenation is less by 150.63 KJ-1. This value is known as resonance energy of benzene.
43. Aromatic characteristics shown in benzene depend upon which factors?
 Aromatic character of benzene is based on the following facts : (i) Resonance bond energy
150.63 k J mol71 of benzene (ii) sp2 hybridization of carbon in benzene (iii) Continuous
transformation of the three n-bonds among 6 carbons in benzene.
44. What is aromatic characteristic of benzene?
 Aromatic or resonance structure is ring shape of molecular orbitals and charge clouds (electron
clouds)
32
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
45. Which type of organic compounds shows aromatic characteristics according Huckel's rule?
 Planar cyclic compounds only.
46. What is main purpose of decarboxylation of carboxylic acid?
 To obtain benzene.
47. Why hydrocarbon compounds are insoluble in water?
 Being non-polar hydrocarbon compounds are insoluble in polar solvents like water.
48. Write down equation to prepare TNT from toluene.
49. Prepare m-xylene from toluene.
50. Write down equation for substitution occurring by acetyl group in benzene.
33
Self Learning Exercise – GSEB – Sem - 2
UNIT – 7
Very Short Questions
Section B
1 What is environment chemistry?
 The study of the sources, reactions, transport, effects and fates of chemical species in the air, soil
and water environment and the effect of human activity on these is called environmental
chemistry.
2 What is meant by degradable pollutants? Give example.
 Those pollutants which decompose on its own by action of micro organisms are called
degradable pollutants. E.g fruits, vegetables, agricultural waste, etc.
3 What is meant by non degradable pollutants?
 Some pollutants remain for decades in their original form without degradation. They are known
as non-degradable pollutants. e.g. dichlordiphenyltrichloroethane (DDT), plastic materials,
heavy metals, radioactive wastes etc.
4 What is called troposphere?
 The lowest region of atmosphere is called troposphere in which all living beings including
human beings reside. It is extended upto 10 km above sea level.
5 What is called stratosphere?
 The region which is above the troposphere and between 10 to 50 km from the sea level is known
as stratosphere.
6 Which components are present in stratosphere?
 Dinitrogen (N2), dioxygen (O2), carbon dioxide (CO2), water vapour (H2O) and argon (Ar) are
present in stratosphere.
7 Which types of disease are caused by entry of SO2 gas during respiration?
 The disease like asthma, swelling & irritation of respiratory tract in human beings.
8 At what temperature NO(g) is formed by reaction between N2(g) and O2(g).
 At 1483 K temperature NO(g) is formed by reaction between N2(g) and O2(g).
9 The smoke exhausted from supersonic planes is the origin of which gases?
 The smoke exhausted from supersonic planes is the origin of NOx gases.
10 10 By which oxide the atmosphere in dense area becomes red-hazzy?
 Due to oxides of nitrogen, the atmosphere in dense area becomes red-hazzy.
11 Which hydrocarbon is present in the smoke produced by smoking bidi-cigarette?
 3, 4- benzpyrene is present in the smoke produced by smoking bidi-cigarette.
12 Write structural formula of benzpyrene.
13 Which disease is caused by 3,4-benzpyrene?
 Cancer is caused by 3,4-benzpyrene.
34
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
14 If a pregnant woman smokes, then miscarriage takes place due to increase in proportion of which
gas?
 If a pregnant woman smokes, then miscarriage takes place due to increase in proportion of
carbon monoxide gas.
15 If the proportion of carboxy-haemoglobin in our body becomes 3 to 4%, then the efficiency of
conduction of which gas of haemoglobin decreases?
 If the proportion of carboxy-haemoglobin in our body becomes 3 to 4%, then the efficiency of
conduction of oxygen gas of haemoglobin decreases
16 The increasing proportion of which gas in air is responsible for global warming?
 The increasing proportion of carbon dioxide gas in air is responsible for global warming.
17 Which mathematician compared the atmosphere of earth with green house?
 In 1882, French Mathematician Jean Fourier, first of all, compared the environment of earth with
green house.
18 Which acids of the atmosphere act as green house gases?
 Carbon dioxide, methane, ozone, chlorofluorocarbons, nitrous oxide and water vapour are
present in atmosphere act ass green house gases.
19 Mention the percentage contribution of green house gases in global warming.
 The contribution of green house gases like CO2, CH4, CFC, O3, N2O and H2O is 50%, 19%, 17%,
8%, 4%, & 2% respectively in global warming.
20 Give the order of green house gases based on GWP.
1000 times
150 times
25 times
CFC
>
N2O
>
CH4
>
CO2
21 How many times more is the global warming potential of CO2 gas than that of CFC gas?
 Compared to carbon dioxide, methane has 25 times, nitrous oxide has 3800
chlorofluorocarbon has 380 lakh times stronger Global Warming Potential.
times and
22 How many times more is the global warming potential of N2O gas than that of CO2 gas?
 The global warming potential of N2O is 3800 times of CO2.
23 Give uses of CFC or Where CFC is used?
 Chlorofluorocarbons are used in aerosols, foam plastic cup, refrigerator, air conditioner,
production of electronic circuits, oil paints and foams used in fire extinguisher that ultimately
enter into atmosphere.
24 Which types of diseases are caused by increase in average temperature of the earth?
 Increase in average temperature of earth may increase the possibilities of contagious diseases
and also diseases like malaria, dengue and yellow fever.
25 Which are the two advantages due to photosynthesis?
 Trees utilize carbon dioxide for photosynthesis and release oxygen. According to one estimate
photosynthesis utilizes 2200 crore tons of CO2 annually from atmosphere and releases 1600
crore tons of oxygen.
26 What is the pH of rain water?
35
Self Learning Exercise – GSEB – Sem - 2
 The pH of rain water is about 5.6
Very Short Questions
27 What is called acid rain?
 When the pH of rain water becomes lower than 5.6 then it is called acid rain.
28 What is the percentage composition of O2 and CO2 in air?
 Air contains 21% of O2 and 0.03% CO2.
29 Why classical smog is called London smog?
 In 1952, such severe smog remained for several weeks in London. Moe than 4000 people died
due to inhalation of the smog. As this classical smog was responsible for the accident in London,
it is conventionally known as ‘London smog’.
30 Why photochemical smog is known as Los Angeles smog?
 The photochemical smog is found frequently in the automobile rich city- Los Angeles of America.
So it is known as ‘Los Angeles Smog’.
31 Which compounds are formed by reaction of NO2 and O3 with uncombusted hydrocarbon?
 NO2 and O3 are strong oxidizing agents. They react with unburnt hydrocarbons present in
polluted air and produce formaldehyde, acrolein and peroxy acetyl nitrate.
32 In which part of the body O3 and peroxy acetylnitrate produce intense irritation?
 Ozone and peroxy acetyl nitrate create acute irritation in eyes.
33 Which difficulties are caused in the body by high concentration of O3 and peroxyacetyl nitrate?
 Ozone and peroxy acetyl nitrate create acute irritation in eyes.
34 What work is really done by green house gases for the earth?
 Actually these green house gases act as blanket of earth. In absence of green house effect the
temperature of earth would be 30 °C lesser than the present temperature.
35 Which evolution should be controlled so as to control the evolution of photochemical smog?
 Evolution of oxide of nitrogen should be controlled to control evolution of photochemical smog.
36 Among which harmful effect, ozone layer provides protection?
 Ozone layer protects all living beings against harmful effect of ultraviolet radiations coming
from sunlight.
37 One molecule of CFC possesses capacity of depletion of how many molecules of O3?
 One molecule of CFC is capable to destroy one lakh O3 molecules in the stratosphere.
38 Which day is known as Ozone Layer Protection Day?
 16th September is known as Ozone Layer Protection Day.
39 Mention the source of pollutant pesticides.
 Chemicals used for killing insects, fungi and weeds
40 Mention the pollutant of the form of radioactive substance.
 Mining of uranium containing minerals
36
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
41 Which institute at the world level has established the standards of the quality of drinking water?
 WHO: World Health Organization .
42 What pH of drinking water is decided by BIS?
 pH of drinking water is decided by BIS is 6.5 of 8.5.
43 More than how many ppm of total dissolved solids in drinking water can cause the irritation in
belley, stomach and intestine?
 Use of drinking water having total dissolved solids concentration higher than 500 ppm causes
possibilities of irritation in stomach and intestine.
44 Which disease is caused by drinking water having proportion of fluoride more than 10 ppm?
 If concentration of fluoride exceeds 10 ppm, it causes fluorosis diseases in which teeth
and bones of a person become weak.
45 Which elements are in trace proportion in the phosphate rocks added in mixed fertilizers?
 Trace of elements like As, Pb and Cd from rock phosphate used for their production.
46 For which class of the animals the weed killers like sodium chlorate and sodium arsenate are found
to be poisonous?
 Sodium chlorate and sodium arsenite used as herbicides are found toxic for
mammals.
47 By the use of which compounds, human deaths are recorded in Iraq?
 Use of methyl mercury and its compounds caused many deaths in Iraq in 1972.
48 Write two names of each natural fertilizers and biofertilisers.
 Natural fertilizers e.g., farmyard manure, compost
 Bio fertilizers e.g., rhizobium, azotobacters, algae etc.
49 Which substances are present in larger proportion in the waste that is obtained from factories of
pesticide industry?
 The waste produced by such industry contains considerable amount of aromatic organic
compounds and acids.
50 Which disease is caused by dinking water in which proportion of nitrate is more than 45 ppm?
 Use of drinking water having the concentration of nitrate higher than 45 ppm causes
possibilities of metheomoglobinemia (blue baby) diseases in children.
51 Which organic materials are in the form of waste in pulp industry?
 The waste produced by such industry contains organic materials like dimethyl sulphide, methyl
mercaptan and inorganic materials like acid, alkali and salts of heavy metals.
52 Write full names of BOD and COD.
 BOD = Biological Oxygen Demand
 COD = Chemcial Oxygen Demand
53 Which substance is more used as bleaching agent in dry-cleaning of clothes?
 Tetrachloroethene (Cl2C=CCl2) was used earlier as solvent for dry cleaning of clothes. Today, the
use of hydrogen peroxide as bleaching agent for washing of clothes has increased which
produces good results using lesser amount of water.
37
Self Learning Exercise – GSEB – Sem - 2
Very Short Questions
54 How much time is required for determination of BOD?
 Time required for determination of BOD is 5 days.
55 Between BOD and COD which analysis is more useful in chemical industries?
 COD is more useful in chemical industries.
56 What are DO1 and DO5 in BOD determination?
 DO1 is the amount of dissolved oxygen on day 1 and DO5 is the amount of oxygen dissolved on
day 5 in the measurement of BOD.
57 Which institute is established in Gujarat state for the control of atmospheric pollution?
 Gujarat Pollution Control Board is established in Gandhinagar to control the environmental
pollution in Gujarat.
38