Download Class XI Chemistry Practics Paper

SAMPLE PAPER-1
CLASS XI
CHEMISTRY
Time: 3 Hours
General Instructions:
All questions are compulsory.
Marks of each question are indicated against it.
Question nos. 1 to 8 are very short answer questions and carry 1 mark each.
Question nos. 9 to 18 are short answer questions and carry 2 marks each.
Question nos. 19 to 27 also short answer questions and carry 3 marks each.
Question nos. 28 to 30 are long answer question and carry 5 marks each.
Use log tables if necessary, use of calculators is not allowed.
Maximum Marks: 70
Q1 How are 0.50 mol Na 2CO3 and 0.50 M Na2CO3 different?
Q2 How many subshells are present in M shell?
Q3 Which property of element is used to classify them in long form of periodic table?
Q4 Write resonance structure of Ozone or sulphurdioxide.
Q5 Write conjugate base for water and NH4+ species.
Q6 What do you understand by Hydrogen economy?
Q7 Find out oxidation number of chromium in K2Cr2O7 molecule
Q8 Indicate sigma and pie bonds in CH2=C=CH2.
1 X 8 = 8 Marks
Q9 Calculate number of photons with a wavelength of 3000pm that provides 1 Joule of energy.2 Marks
Q10 Explain why bond angle in NH3 is more than in H2O molecule though both have sp3 hybridization. 2 MarksQ11 At constant temperature if the
pressure of a fixed mass of gas is doubled what happens to its volume ? Which law governs this behavior of gases? 2 Marks
Q12 How many grams of oxygen is required for complete combustion of 29g of butane as per the equation C4H10+4.5O22CO2+5H2O
2 Marks
Q13 Calculate bond order of oxygen molecule. List all the information provided by the bond about this molecule.2 MarksQ14 Calculate the total pressure
in a mixture of 16 g of oxygen and 4g of Hydrogen confined in a vessel of 1dm-3 at 27 degree celsius. (Molar mass of oxygen 32 Hydrogen 2 R= 0.083bar
dm3 K-1mol-1)
2 Marks
Q15 Balance following equation in acidic medium showing all steps,
Br2 + H2O2- BrO2 + H2O
2 Marks
Q16How are silicones prepared? Write necessary reaction. Write two uses of silicones. 2 marks
Q 17 What is demineralised water? How is it obtained?
2 Marks
Q18 What is the reason of diagonal relationship of elements? Write two properties of any two diagonally related elements.
Or
Give reasons
(1) why alkali metals when dissolved in Liquid ammonia give blue solution?
(2)Beryllium and Magnesium do not impart colour to the flame while other members do.
Q19 (1) State Heisenberg s Uncertainty principle.
(2) Write electronic configuration of Cu metal (Z=29) and Cr3+ ion.
(3)Which orbital is represented by n=4 and l=3?
3 Marks
Q20 Explain why
(1) Halogens act as good oxidizing reagent.
(2)Electron gain enthalpy of inert gases is zero.
(3)Ionization enthalpy of Mg is higher than that of Na.
3 Marks
Q21 (1) What do you mean by Bond Enthalpy?
(2) Calculate bond enthalpy of Cl---Cl bond from following data.
CH4(g) + Cl2 (g)--CH3Cl(g) +HCl (g)
ΔH-= --109.3kJ mol-1
Bond enthalpy of C—H Bond = 413kJ, C—Cl Bond =326 kJ and H—Cl Bond =431kJ
mol -1
3 Marks
Q22 (1) What are extensive properties?
(2) Write Gibbs free energy equation giving meaning of each term used.
(3) Under what condition Δ U=
ΔH ?
3 Marks
Q23Write chemical equation only for preparation of
(1) Plaster of Paris (2) Quick lime (3) slaked lime.
3 Marks
Q24 (1) What do you mean by functional isomerism?3 Marks
(2) What are electrophiles?
(3) What is inductive effect ? Give an example.
Or
(1) Write IUPAC names for C6H5CH2CHO and (CH3)2—CH(NH2)—CH3
(2) Write an example of geometrical isomerism.
(3) What do you mean by electromeric effect?
3 Marks
Q25(1) Draw eclipsed and staggered conformations of ethane.
(2)Write one equation each to show Wurtz reaction and Friedal craft alkylation.
3 Marks
Q26 (1) How nitrogen is detected in an organic compound.?Wrirenecessary reactions.
(2) How a molecular formula is different from empirical formula?
3 Marks
Q27 (1) What do you mean by green chemistry?
(2) Explain terms BOD and COD with reference to environmental chemistry. 3 Marks
Q28 (1) For the reaction N2(g) + 3H2 (g)↔2NH3(g) the value of Kp is 3.6 x102-+ 2-2 at 500 K. Calculate the value of Kc for the reaction at the same
temperature. R=0.083 bar L K-1 mol-1.
(2) What do you understand by (1) Common ion effect (2) Buffer solution.3+2 Marks
Or
For the reaction PCl5↔PCl3+Cl2 at 473K the value of equilibrium constant Kc is 8.3 x10 -3
(1) Write an expression for Kc
(2)What is the value of Kc for reverse reaction at same temperature.
(3) What would be effect on Kc if pressure is increased.
(2) State Henry’s Law. Write pH value of 1x10-5 M HCl solution.
3+2 Marks
Q29 Give reasons for
(1)[SiF62]- is known whereas [SiCl6]-2 is not known.
(2) Diamond is a covalent solid, yet it has highest Melting Point.
(3) Boric acid is considered a weak base.
(4) BF3 behaves as Levis acid.
(5) CO2 is a gas while SiO2 is a solid at room temperature.
Or
(1) What are fullerenes?-(2) Why is boric acid monobasic?(3)What is inert pair effect?
(4)Why is PbCl2 is a good oxidizing reagent? (5)Write the formula of inorganic benzene.
Q30 (1) State Markovnicoff’s rule.Using this write the reaction of propene with HCl.
(2) Carry out following conversions
(1) Ethyl alcohol to ethane. (2) Sodium acetanilide to benzene. (3) Benzene to nitrobenzene. 2+3 Marks
Or
(1) Write two reactions to show acidic nature of ethyne
(2) Complete the following reactionsozone/Zn/H2O
(1) CH3—CH=CH2

aquous KMnO4
(2)CH3—CH=CH2

(3)CH=CH + Br2 water 
SAMPLE PAPER-2
Class XI
Time: 3 hours
M.M-70
General instructions:
1.
All questions are compulsory
2.
Marks for each question are indicated against each
3.
Question nos. 1-8 are very short answer questions and carry one mark each. Answer these questions in one word or about one
sentence each.
4.
Question nos. 9-18 are short answer questions and carry 2 marks each. Answer these questions in about 30 words each.
5.
Question nos. 19-27 are short answer questions and carry 3 marks each. Answer these questions in about 40 words each.
6.
Question nos. 28-30 are long answer questions and carry 5 marks each. Answer these questions in about 70 words each.
7.
Use log table if necessary, use of calculators is not allowed.
Q1 What does a mole represent?
Q2 Why 4s orbital is filled earlier to 3d orbital?
Q3.Locate the position of element with atomic number 33.
Q4. Define Charles law.
Q5.What is the entropy change when a liquid vaporizes?
Q6.What is the conjugate acid of NH3?
Q7.Which out of the two- lithium or sodium forms nitrides?
Q8.What effect does branching of an alkane has on its boiling point?
Q9.How many grams of NaOH should be dissolved to make 100 ml of 0.15 M NaOH solution?
Q10.(a.) why Rutherford’s model was discarded?(b.) write the electronic configuration of S 2Q11.The reaction of NH2 CN(s) with oxygen was affected in a bomb calorimeter and ∆U was found to be -742.7 Kj/mol of cyanamide at
298 K. calculate enthalpy change for the reaction NH2CN(s)+3/2 O2 (g) 
N2 (g) + CO2 (g)+H2O(l)
OR
Calculate the enthalpy change for the reaction:-H2 (g) +Cl2 (g) 
2HCl (g)
Given that bond energies H-H, Cl-Cl and H-Cl bonds are 433,244 and 431Kj/mol respectively
Q12.Write the equilibrium constant for the reaction :(a)
(b) Cu(NO3)2 (s)
Fe3+(aq) + 30H- (aq)Fe(OH)3 s
2CuO (s) + 4NO2(g) + O2 (g)
Q13.Why is Li2CO3 decomposed at a lower temperature whereas Na2CO3 is decomposed at a higher temperature?
Q14.Acount for the following.-
(i) Na and K impart colour to the flame but Mg does not.
(ii) Lithium is the best reducing agent in aqueous solution?
Q15.(a) What is inert pair effect? Give one example.
(b) Why is CO2 gas whereas SiO2 is solid?
Q16.(a) Which of the following carboanion is more stable? (I) (CH3)3CCH2Ɵ (ii) CH3CƟHCH2CH3 (iii) CH3CH2CH2Ɵ
(b) Draw the resonating structures for SO3.
Q17.Explain the following(a)CCl4 does not give white precipitate with silver nitrate solution on heating. Why?
(b) Why is O2NCH2O- is expected to be more stable than CH3CH2OQ18.complete the following(a)CH3Br + Mg
Q19.The kinetic energy of an electron is
4.55x10 -25 J.
dry ether
the mass of electron
(b) 2CH3CH2I + Na
9.1x10-31 Kg.
dry ether
Calculate velocity, momentum and the wavelength
of the electron?
20.Give reasons:
(a) Size of cation is always smaller than the parent atom.
(b) Ionization enthalpy of nitrogen is greater than that of oxygen.
(c) Electron gain enthalpies of beryllium and magnesium are positive.
Q21.What will be the pressure exerted by mixture of 3.2 g of methane and 4.4 g of carbon dioxide contained in a 9 dm 3 flask of 27o C.
Q22.What are factors responsible for spontaneity of reaction .Write in brief?
Q23.The pH of 0.1 M solution of HCNOƟ is 2.34. Calculate the ionization constant for the acid and its degree of ionization in the solution.
Q24. (a) Identify the substance oxidized and reduced:
N2H4 + 2H2O2
N2 + 4H2O
(c) Calculate the oxidization No. of Carbon in CH3CH2OH
(d) Balance the following:MnO4–+Fe2+
Mn2++Fe3+(Acidic medium)
OR
.(a) Balance the following equation Fe2++Cr2O72- → Fe3++ Cr3+
(b) What is salt bridge. Write its application also
Q25.(a) Give two properties of Water which are due to Hydrogen bonding.
(b) Explain the Structure of H2O2.
Q26.An org. compound contain 69% carbon and 4.8% Hydrogen, the remainder being oxygen, Calculate the masses of carbon
dioxide and water produced when 0.20 g of this compound is subjected to complete combustion.
Q27.(a) What do you mean by BOD?
(b) Give difference between classical smog and photo chemical smog.
Q28.Give reason:
(a) Concentrated HNO3 can be transported in aluminium containers.
(b) Graphite is used as lubricant.
(c) A mixture if a dil. NaOH and aluminuim piece is used to open holes.
(d) Carbon shows catenation but silicon does not.
(e) Tin (II) is a reducing agent but Pb(II) is not.
OR
A certain salt(X) gives the following results
(a) Its aqueous solution is alkaline to litmus.
(b) It swells up to glassy material (Y) on strong heating.
(c) When concentrated H2SO4 is added to hot solution of X, white crystals of an acid Z separates out.
(d) Write equations for ii and iii. Also identify X, Y, Z.
Q29.(a) i) How many sigma and Pi bonds are present in CH2=CH—C≡CH
ii) Why H2+ is more stable than H2Ɵ? iii) Why is B2 molecule paramagnetic?
(b)Discuss orbital structures of following molecules on the basis of hybridization
i) BH3 ii) C2H2
OR
a)
on the basis of VSEPR theory explain shapes of following
b)
Which of the two NH3 or NF3 has higher dipole moment?
c)
Why N2 is more stable than O2?
d)
Why is ethyl alcohol miscible with water?
(1) NH3
(2)
H2O
30.a) Why terminal alkynes are acidic in nature?
b) Write IUPAC name of followi CH3—C—CH2—COOH
║
O
c) Write the following conversions i) Propene to 2-3 Dimethyl butaneii) Ethane to Ethyneiii) Benzene to Benzene sulphonic acid
OR
write short notes on (i)Wurtz reaction
(ii)Markonikoff’s rule
(iii)Freidel crafts alkylation
(a)A hydrocarbon Y decolourizes bromine water. On ozonolysis it gives 3-methyl butanal and formaldehyde. Give the name and formula of
the compound.
(b)Why is benzene extraordinary stable though it contain 3 double bonds?