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1-
A compound contains 12.1% C, 16.2% O, and 71.7% Cl by mass.
The empirical formula of this compound is:
(a) C2O2C12
**(c) COC12
2-
**(b) 152.3
(c)
247.9
(d)
The number of moles of hydrogen molecules that are required to
react with 0.6 mol C to give butane, C4H10 is:(a)
(c)
4-
CO2C12
(d) C2O3C1
The mass of silver, Ag, in grams which can be obtained from
250.0 g of an ore that is 70% Ag2S is:
(a) 125.3
107.8
3-
(b)
1.5 mol
3.0 mol
**(b) 0.75 mol
(d) 0.375 mol
The number of atoms of sulfur in 1.24 mol CaSO4 is:
(a)
(c)
6.02x1023
8.50x1023
(b) 1.24x1023
**(d) 7.46x1023
5- A 1.261 g sample of caffeine contains 0.624 g C, 0.065 g H, 0.364 g N
and 0.208 g 0. Thus, the empirical and molecular formulas of
caffeine, if the molecular weight is 194 g, are respectively:
(a) C5H5N3O, C10H10N6O2
**(c) C4H5N2O, C8H10N4O2
6-
(b)
(d)
C3H5N2O, C9Hr5N6O3
C3H4N2O, C4H8N4O2
How many atoms of bromine are there in 4.85 mol CBr2Cl2?
(a) 8.55x 1023
**(c) 5.85 x 1024
7.02 x 1023
4.85x1024
(b)
(d)
١
7-
If a compound is composed of 43.7%P and 56.3% O by weight
thus its empirical formula is:
(a)
8-
P2O3
**(c) P2O5 (d)
PO3
The number of isopentyl acetate, C7H14O2 molecules and carbon
atoms in 10-3 g C7H14O2 are (respectively):
(a)
(c)
9-
PO2 (b)
8.55x1022 and 5.7x1023
5.00x1018 and 7.0x1017
**(b) 5x1018 and 3.5x1019
(d) 5x1015 and 4.0x1016
The empirical formula and molecular formula of a compound
that gives the following analysis (in mass percent) 71.65% Cl;
24.27% C; 4.07% H are respectively. (The molar mass of the
compound is 98.96 g/mol)
**(a) ClCH2 and Cl2C2H4
(c) ClCH2 and Cl3C3H6
(b)
(d)
C12CH3 and Cl2CH3m
Cl2C2H4 and ClC2H4
10- Inorganic acid has the following percent composition %H =
4.89%, %B = 17.5%, %O =77.7 %, then its formula is:
(a)
H2BO2
(b)
HBO3
(c)
H2BO3
**(d) H3BO3
……………………………………………………………………………..
11- The mass of KOH in grams required to prepare 75 mL of 0.4M
KOH solution is:
(a)
5.6
(b)
22.8
(c)
11.4 **(d) 1.68
12- Methanol CH3OH, is prepared industrially as follow:
CO(g) + 2H2(g) → CH3OH(g)
If 35.4 g CO and 10.2 g H2 reacted in a reaction vessel. How
many grams of methanol would be produced in a complete
reaction?
**(a) 40.5g
(b) 35.4g
(c)
٢
12.0 g
(d) 60.6g
13- Methyl salicylate C8H8O3 is prepared by the following reaction:
C7H6O3 + CH3OH → C8H8O3 + H2O
In an experiment, 1.50 g of C7H6O3 is reacted with excess of
methanol. The yield of, C8H8O3 is 1.31 g. The percentage yield
is:
(a)
(c)
50.5 %
99.5%
(b) 88.5%
**(d) 79.3%
14- How many milliliters of 0.126 M HClO4 are required to give
0.00752 mol HClO4?
(a) 41.9 mL
**(c)59.7 mL
(b)
75.5 mL
(d) 21.6 mL
15- A sample of oxalic acid, H2C2O4, weighing 1.274 g is placed in
100 mL volumetric flask, which is then filled to the mark with
water. The molarity of the solution is:
(a)
(c)
0.1274 M
0.2731 M
**(b) 0.1415 M
(d) 0.4l35 M
16- What volume of 0.250 M HNO3 reacts with 42.4 mL of 0.150 M
Na2CO3 in the following reaction?
2HNO3(aq) + Na2CO3(aq) → 2NaNO3(aq) + H2O(ℓ) + CO2(g)
**(a) 50.9 mL
(c) 25.0 mL
(b)
(d)
42.4 mL
15.0 mL
17- The volume of water (in mL) needed to dilute 20 mL of 0.25 M
K2CrO4 solution to prepare 0.05 M solution is:
(a)
50
(b)
120
(c)
40
**(d) 80
18- Methanol (CH3OH) can be manufactured as follow:
2H2(g) + CO(g) → CH3OH(ℓ)
If 68.5 Kg CO(g) is reacted with 8.60 Kg H2(g) and 3.57xl04 g of
CH3OH is produced, the percent yield of CII3OH is:
٣
(a)
(c)
70.0%
30.0%
**(b) 52.0%
(d) 68.0%
19- The mass of solid NaCl that must be added to 1.50 L of a 0.10 M
AgNO3 solution to precipitate all Ag+ ions in the form of AgCl
according to the following equation:
NaCl + AgNO3 → AgCl(s) + NaNO3,
is:
**(a) 8.77 g
(c) 16.22 g
(b) 4.33 g
l0.ll g
(d)
20- 9.0 g of CS2(ℓ) and 3.0 g of NH3(g) are reacted to Form
NH4SCN(s) according to the equation:
CS2(ℓ) + 2NH3(g) → NH4SCN(s) + H2S(g)
After the reaction was finished 6.0 g of NH4SCN (s) was obtained
from the reaction mixture. the percentage yield of NH4SCN in
this experiment is:
**(a) 89.47%
(c) 95.8%
(b)
50.0%
(d) 67.0%
………………………………………………………………..
21- The volume of 0.3625 M Na2S2O3 solution in mL required to
react completely with 1.256 g of I2(s) according to the following
equation:
2Na2CO3 (aq) + I2(s) → 2NaI(aq) + Na2S4O6 (aq)
is:
(a)
54.6 **(b) 27.3
(c)
13.6 (d)
36.4
22- The empirical formula of a compound consists of 0.1773 g of Cl
and 0.1396 g of Fe is:
(a) FeCl3
FeCl
**(b)
FeCl2
٤
(c)
Fe2Cl6
(d)
23- The mass of copper that is obtained by reacting 0.5 g of Al and a
solution containing 6.56 g Cu(NO3)2 according to the following
equation
2A1(s) + 3Cu(NO3)2 → 2A1(NO3)3 + 3Cu
is:
(a)
(c)
2.22 g
0.50 g
**(b) 1.76 g
(d) 1.18 g
24- Mercuric bromide is produced according to
Hg(ℓ) + Br2(ℓ) → HgBr2(s)
The mass of HgBr2 that can be produced from the reaction of
10.0 g Hg and 9.00 g Br2 is
** (a)
19.00 g
(c) 7.50 g
(b) 48.0 g
(d) 15.0 g
25- A solution is prepared by dissolving 0.5842 g oxalic acid
(H2C2O4) in enough water to make 100.0 mL of solution. A 10.0
mL of the above solution is then diluted to a final volume of'
250.0 mL. The final molarity of the solution is:
(a)
(c)
6.488X10-2 M
3.244 x 102 M
(b) 1.300X10-3 M
**(d) 2.595x10-3 M
26- A 25.00 mL sample of HCl solution requires 24.16 mL of 0.106 M
sodium hydroxide (NaOH) for complete neutralization;
HCl(aq) + NaOH(aq) → NaCl(aq)
The concentration of the original HCl solution is:
(a) 0.204 M
**(c) 0.102 M
(b)
(d)
0.318 M
0.002 M
27- Ammonia is prepared by the reaction:
3H2(g) + 2N2(g) → 2NH3(g)
If 1.34 mol of N2 was reacted with 3 mol of H2; the limiting
reactant will be:
(a) H2
(d) No limiting reactant
**(b) N2 (c) NH3
٥
28- Consider the following reactions (equations are not
balanced):
1) Cu + Cl- + As4O6 → CuCl + As
2) Cu(NH3)2+4 + S2O-4 → SO-3 + Cu + NH3
copper is acting as:
(a)
(b)
(c)
Oxidizing agent in both equations.
Reducing agent in both equations.
Oxidizing agent in equation (1) and reducing agent in equation
(2).
**(d) Reducing agent in equation (1) and oxidizing agent in equation
(2).
29- In the conversion of NH3 to NO
(a) Nitrogen is reduced and gains 5 e**(b) Nitrogen is oxidized and loses 5 e(c) Nitrogen is reduced and gains 3 e(d) Nitrogen is oxidized and gains 3 e30-To balance the following half reaction in acid medium:
ICCl → IO3- + ClIt is necessary to add
(a)
(c)
5 e- to the left side
4 e- to the left side
(b) 5 e- to the right side
**(d) 4 e- to the right side
31- The following reaction:
Cu2+ + 4 NH3
→
[Cu(NH3)4]2+
(a) Is an oxidation-reduction reaction?
(b) Is a Bronsted-Lowry acid base reaction?
**(c) Is a Lewis acid-base reaction?
(d) None of the above
٦
32- Consider the following reactions (equations are not balanced):
1- NH3 + O2 → N2 + H2O
2- HNO3 + S → NO + SO2 + H2O
Nitrogen is acting as:
(a) Oxidizing agent in both equations.
(b) Reducing agent in both equations.
**(c) Reducing agent in eq.(1) and oxidizing agent in eq.(2).
(d) Reducing agent in eq. (2) and oxidizing agent in eq. (1).
33- The oxidation states (numbers) of nitrogen and of sulfur in
ammonium sulfate, (NH4)2SO4 are:
(a)
(c)
3 and 5 respectively.
+3 and –6 respectively
(b) -6 and 4 respectively.
**(d) -3 and +6 respectively.
34- In which of the following changes does the substance on the left
function as an oxidizing agent? (The equations are not balanced).
(a)
(c)
Fe 2+ → Fe3+
2H2O → O2 + 4H+
**(b) NO2 → N2O22(d) NH3 → NH4+
35- In the reaction of NH4+ to form NO2-, the oxidation state number
of nitrogen is:
(a) Increased by 5
**(c) Increased by 6
(b)
(d)
Decreased by 3
Increased by.2
36- To balance the reduction half of the fo1lowing equation in acid
medium:
Zn + NO3- → Zn2+ + NH4+
(a) We add 2 electrons to the left side.
(b) We add 2 electrons to the right side.
(c) We add 8 electrons to the right side.
**(d) We add 8 electron to the left side.
٧
37- In balancing the following half-reaction in acidic solution:
8H+ + MnO4- → Mn2+ + 4H2O
(a) 6 electrons are added to the left side
(b) 6 electrons are added to the right side
**(c) 5 electrons are added to the left side
(d) 5 electrons are added to the right side.
38- In balancing the following equation;
P4 → PH3 + H2PO2is basic solution the final equation is
**(a) 12OH- + 4P4 + 12H2O → 4PH3 + 12H2PO2(b) 4P4 + 2H2O → 4PH3 + 12H2PO2- + 12H+
(c) 12H+ + 2P4 → H2PO4- + PH3 + 8e(d) Non of the above.
39- The oxidation number of (Cl) in NaO2Cl is:
(a)
-1
(b)
+1
(c)
+2
**(d) +3
40- According to the following balanced redox reaction:
16H+ + 2MnO4- + 5C2O42- → 10CO2 + 8H2O + 2Mn2+
then one of the following statement is correct:
(a)
(c)
MnO4- is a reductant.
C2O42- is an oxidant.
**(b) C2O42- is a reductant.
(d) H+ is a reductant.
41- The total number of electrons involved in the following redox
reaction:
Fe(s) + Cl2 → FeCl3
is:
(a)
4
** (b)
6
(c) 2
٨
(d)
8
42 The molar ratio of permanganate and oxalate solutions reacting
in an acidic medium
MnO4- + C2O42- → Mn2+ + CO2
(a)
1 : 1 (b)
3:2
(c)
is:
5 : 2 **(d) 2 : 5
43- When the following equation is balanced for basic solution.
N2H4 + Mn(OH)3 → Mn(OH)2 + NH2OH
**(a) There are no OH ions among either the reactants or products.
(b) The coefficient of N2H4 is 3.
(c) There are 2OH- on the left.
(d) The coefficient of Mn(OH)3 is 2.
…………………………………………………………………..
44- The density of CH4 gas at 25oC and 1.50 atm. is:
**(a) 0.981 g/L
(c) 1.00 g/L
(b)
(d)
0.891 g/L
0.700 g/L
45- A mixture of 40.0 g of oxygen and 40.0 g of helium gases has a
total pressure of 0.90 atm. The partial pressure of the oxygen in
this mixture is:
(a) 0.799 atm
**(c) 0.100 atm
(b)
(d)
0.345 atm
0.800 atm
46- A 50 mL sample of oxygen at 25oC and 120 torr and a 100 mL
sample of nitrogen at 25oC and 160 torr are both placed in a 200
mL flask at 25oC. What is the final pressure in the 200 mL flask?
(a)
(c)
250 torr
140 torr
(b) 280 torr
**(d) 110 torr
47- A 16 gram- sample of oxygen gas has a volume of 11.2 liters at
standard pressure. What is the temperature of oxygen?
**(a) 0oC (b)
100oC
273oC
(c)
٩
(d)
373oC
48- If the density of gas X at STP is 1.965 g per liter, the molar mass
of this gas is:
(a)
(c)
1.0 g mol-1
11.2 g mol-1
(b)
2.0 g mol-1
**(d) 44.0 g mol-1
49- O2 gas is collected over water at 25oC. If the volume of the gas is
245 mL at a pressure of 758 torr, (v.p. of H2O = 23.8 torr). Thus
the volume of dry oxygen at STP is:
**(a) 2l7 mL
(b)
224 mL (c)
2584 mL (d)
7 mL
7- When the Kelvin temperature of a gas is halved and the pressure
is held constant, the volume:
(a)
(c)
Doubles
Remains constant
**(b) Halves
(d) Can not be determined
50- Copper metal may be oxidized to a Cu1+ ion by the following
equation:
2Cu + 2HCl → 2CuCl + H2
If 6.4 g of Cu is oxidized, what volume of hydrogen (at STP) is
evolved?
(a) 22.4 L
0.05 L
(b)
12.2 L
**(c)
1.1 L
(d)
51- At extremely low pressure, the van der Waals equation for one
mole may be written as
(a)
(c)
P(v + b) = RT
(P – a / v2) (v + b) = RT
(b) (P – a / v2)v = RT
**(d) Pv = RT
52- 60.0 mL of O2 was collected over water at a total pressure of 755
torr and at a temperature of 25oC. The vapor pressure of water
at 25oC is 24 torr. How many moles of O2 were collected?
(a)
2.44 x 10-3 mol
(b)
١٠
6.89 x 10-3 mol
(c)
2.51 x 10-3 mol
**(d) 2.36 x 10-3 mol
53- What is the molecular mass of a gas whose density is 3.79 g/L at
25oC and a pressure of 729 torr?
(a)
153 **(b) 97
(c)
118 (d)
64
54- The number of oxygen molecules in 150 mL flask at 1 torr
pressure and 25oC is:
(b) 4.81x1021
(a) 6.02x1023
(c) 3.66x1021
**(d) 4.81x1018
55- The density of a gas is 1.347 gL-1 at 80.0 kPa and 27oC. If the
empirical formula of the gas is CH2, the molecular formula is:
(a) CH2
**(c) C3H6
(b)
(d)
C2H4
O4H8V
56- The pressure (in atm.) exerted by 1 mol CO2 in 150 mL vessel at
20oC, using the van der Waals equation is:
(a = 3.592 atm L2 mol-2& b = 4.267x10-2 L mol-1)
(a)
6.23 (b)
3.115
(c)
0.26 **(d) 1.59
15A balloon filled with helium has a volume of 10,000 liters at
atmospheric pressure and 30oC. The weight (in kilograms) of
helium needed to fill the balloon is:
(a)
2.455
(b) 8.155
**(c) 1.610
(d) 0.963
57- Which of the following statements are correct:
1) The measured volume of a real gas is lower than the volume
of the gas if it were ideal
2) The measured volume of a real gas is higher than the
volume of the gas if it were ideal.
3) The measured pressure of a real gas is lower than the
pressure of the gas if it were ideal.
١١
58- The measured pressure of a real gas is higher than the
pressure of the gas if it were ideal.
(a)
1, 3 (b)
1, 4
**(c) 2, 3 (d)
1, 2
……………………………………………………………………………
59- All of ∆Ho given below are heats of formation except:
(a) C (s) + 2 H2 (g) → CH4 (g)
**(b) 2 H2 (g) + O2 (g) → 2 H2O (g)
(c) 1/2 N2 (g) + 3/2 H2 (g) → NH3 (g)
(d) 1/2 H2 (g) + 1/2 C12 (g) → HCl (g)
∆Ho
∆Ho
∆Ho
∆Ho
60- One of the following statements is wrong about the enthalpy of
the reaction ∆Hr
(a) ∆Hr depends on the quantities of the reactants and products.
**(b) ∆Hr of the forward reaction equals ∆Hr of the reverse reaction.
(c) ∆Hr depends on the physical states of the reactants and
products.
(d) ∆Hr depends on temperature and pressure of the reaction.
61- Given: ∆Hfo [CO2(g)] = -394 kJ mol-1; ∆Hfo [H2O(ℓ)] = -286 kJ
mol-1; ∆Hfo [C6H12O6(s)] = 1260 kJ mol-1; ∆Horeac. for the
following reaction is:
6CO2 (g) + 6H2O (ℓ) = C6H12O6 (s) + 6O2 (g)
**(a) + 2820 kJ
(c) - 2460 kJ
(b)
(d)
- 2820 kJ
+ 2450 kJ
62- When comparing energies of a double and a single bond we find
that when we break a double bond
(a) A higher energy is given out.
(b) A lower energy is given out.
**(c) A higher energy is taken in.
(d) A lower energy is taken in.
١٢
63- Given
2C(graphite) + 2H2(g) = C2H4(g); ∆Hfo = +52.30 kJ/mole
2C(graphite) + 3H2(g) = C2H6(g); ∆Hfo = - 84.68 kJ/mole
The standard enthalpy change, ∆Ho in kJ for the reaction:
C2H4 (g) + H2 (g) = C2H6 (g) is:
(a) - 52.30
**(c) -136.98
(d)
(b) +136.98
+169.40
64- The combustion of glucose is described by:
C6H12O6(s) + 6O2(g) = 6CO2(g) + 6H2O(ℓ); ∆H = 2.82 x 103 kJ
The mass of glucose (in grams) that must be burned to produce
47.0 kJ of heat is:
**(a) 3.00 (b)
6.95
(c)
4.29 (d)
2.25
65- if ∆Hreaction has a positive value, then
**(a) Bonds broken are stronger than bonds formed.
(b) Bonds broken are weaker than bonds formed.
(c) Bonds broken are of equal strength to bonds formed
(d) ∆Hreaction value has nothing to do with bond energies.
66- What equation must be used to represent the formation of nitric
acid, HNO3(ℓ), when we want to include its value of ∆Hfo
HNO3(ℓ) = -173.2 kJ mol-1?
(a) H2(g) + N2(g) + 3 O2(g) → 2HNO3(ℓ);
∆Hfo = -346.4 kJ mol-1
(b)1/3H2(g) + 1/3N2(g) + O2(g) → 2HNO3(ℓ); ∆Hfo = -115.5 kJ mol-1
**(c)1/2H2(g) +1/2N2(g) +3/2O2(g)→ HNO3(ℓ); ∆Hfo =-173.2 kJ mol-1
(d)NO2(g) + H2O(ℓ) → 4HNO3(ℓ) + 1/2H2(g) ∆Hfo =-173.2 kJ mol-1
67- Which of the following expressions is incorrect:
(a) ∆E = qv
(b) ∆E = q - P∆V (if the only work available is of expansion)
**(c) ∆E= ∆H +P∆V
(d) ∆H =qp
١٣
68- Given the following data:
H2(g) + O2(g) → H2O2(ℓ);
∆Ho = - 188 kJ
H2(g) + ½O2(g) → H2O(ℓ),
∆Ho = - 286.4 kJ
The standard enthalpy ∆Ho for the following reaction in kJ will
be:
H2O2(ℓ) → H2O(ℓ) + ½O2(g),
∆Ho = ?
**(a) -98 (b)
-628
(c)
+176 (d) +118.4
69- Propylene has the structure
H
H
C
C
C
H
H
H
H
o
if ∆Hf of propylene is 8 kJ/mole. Calculate the (C=C) bond
energy (in kJ mol-1): given the following data: ∆Hfo of gaseous C
atom = 715 kJ/mole
∆Hfo of gaseous H atom = 218 kJ/mole
(C-C) bond energy = 348 kJ/mole
(C-H) bond energy =415 kJ/mole
(a)
179 (b)
486
**(c) 607 (d)
348
70- One of the following relationships is incorrect:
(a) ∆E = ∆H-∆ (PV)
(b) ∆E = ∆H - ∆ (nRT) assume ideal gas
**(c) ∆E = qp + P∆V (at constant pressure)
(d) ∆H= qp
71- Given:
C2H6 (g) + 7/2O2 (g) → 2CO2 (g) + 3H2O (ℓ); ∆Ho = -1460 kJ
[∆
∆Hf0 (CO2) = -393.7 kJ; ∆Hf0 (H2O) = -285.6 kJ ] then ∆Hfo
(C2H6) in kJ/mol equals:
(a) +184.2
-184.2
(b)
-780.7
١٤
(c)
+780.7
**(d)
72- Given the following thermochemical equations:
(i) 4NH3 (g) + 3O2 (g) → 2N2 (g) + 6H2O (ℓ),
∆Ho = -1531 kJ
(ii) N2O (g) + H2 (g) → N2 (g) + H2O (ℓ);
∆Ho=367.4 kJ
(iii) H2 (g) + ½O2 (g) → H2O (ℓ),
∆Ho = -285.9 kJ
Calculate ∆Ho for the reaction (in kJ)
2NH3 (g) + 3N2O (g) → 4N2 (g) + 3H2O (ℓ), ∆Ho =?
(a)
(c)
- 2220 1
+ 890.4
**(b) - 1010.0
(d) - 1102.2
73- If the heat evolved by the combustion of 3.00 gms of glucose,
C6H12O6(s) in a bomb calorimeter (constant volume) is 47.0 kJ.
Then for one mole of glucose, the quantity of heat evolved (in kJ)
is (according to the equation):
C6H12O6 (s) + 6O2 (g) → 6CO2 (g) + 6H2O (ℓ);
∆H = ?
**(a) 2.82x103
(c) 6.15x103
(b)
(d)
2.22x102
1.95x104
74- Given the following data:
B2H6 (g) + 6H2O (ℓ) → 2H3BO3 (s) + 6H2(g), ∆Ho = -493.4 kJ
∆Hfo of H3BO3(s) is – 1088.7 kJ/mol ∆Hfo of H2O (ℓ) is
-285.9 kJ/mol. Calculate the standar enthalpy of formation of
B2H6(in kJ/mole).
………………………………………………………………………
١٥
75- Which is an example of a polar covalent molecule?
(a)
KCl (b)
A12(SO4)3 **(c) HCl (d)
H2
76- The weakest bond among the following is:
(a)
(c)
Ionic
Metallic
(b) Covalent
**(d) Hydrogen bond.
77- If the bond energies of the following are:
(A - A) = 420 kJ/mole
(B - B) = 600 kJ/mole
(C - C) = 650 kJ/mole
Then the vibrational frequencies could be arranged in order as
follows:
(a) A2
(b) A2
**(c) A2
(d) A2
>
<
<
=
B2
B2
B2
B2
>
=
<
=
C2
C2
C2
C2
78- On breaking a bond the energy is:
(a) Released and its amount depends on its order.
(b) Released and its amount increases with increase of its length.
**(c) Absorbed and its amount depends on its order.
(d) Absorbed and its amount does not depend on any variable.
79- Element X has an electronic configuration of 1s2 252 2p6 3s2 3p1.
This element will combine with the phosphate ion (PO43-) to form
a compound with the formula:
**(a) XPO4
(c) X2PO4
(b)
(d)
١٦
X(PO4)2
X2(PO4)3
80- One of the following statements is not correct:
(a)
Born-Haber cycle relates the lattice energy of an ionic
compound to other theoretical data.
(b) The amount of energy released when one mole of ionic crystal
is formed from its constituent ions in the gaseous phase is
known as lattice energy.
**(c) Lowering the energy of a system is associated to a decrease in
its stability.
(d) An ionic bond is formed by the transfer of one or more valence
electrons of one atom to the valence shell of the other.
81- One or more of the following molecules obey(s) octet rule:
2) CH4
3) BC13
4)
SF6
1) H2
(a)
1,4
(b) 2,4
**(c) Only 2
(d)
2,3
82- When comparing energies of a double and a single bond we find
that when we break a double bond.
(a) A higher energy is given out.
(b) A lower energy is given out.
**(c) A higher energy is taken in.
(d) A lower energy is taken in.
83- The type of bond between two similar non-metallic atoms is:
(a)
(c)
A pure ionic bond
**(b) A pure covalent bond
50% ionic and 50% covalent
(d) No bond is formed
84The N-N bond order, bond length and bond energy in the
following compounds: N≡N, N=N=O, and H—N—N—H respectively
are:
Bond Order
(a) Increases
**(b) Decreases
(c) Decreases
(d) Increases
Bond Length
Increases
Increases
Increases
decreases
١٧
Bond Energy
Decreases
Decreases
Increases
Increases
85- One of the following statements is correct:
(a) A molecule with non-polar bond can be polar.
(b) A molecule with polar bond must be polar.
**(c) A polar molecule must have polar bond.
(d) All of the above
86- One of the following arrangement is correct as far as their
increase polarity:
**(a) BF3 < H2S < H2O
(c) H2O < H2S.< BF3
(b)
(d)
H2S < H2O < BF3
BF3 < H2O < H2S
87- The lattice energy of LiCl (s) according to the following
information:
Li (s) → Li (g)
∆H = 155.2 kJ
+
∆H = 520.0 kJ
Li (g) → Li (g)
C12(g) → 2 Cl(g)
∆H = 242.8 kJ
Li (s) + 1/2 Cl2 (g) → LiCl (s)
∆H = - 408.8 kJ
Cl(g) → C1 (g)
∆H = - 348.0 kJ
is:
(a) - 978.8 kJ
**(b) - 857.4 kJ
(c) - 1553.1 kJ
(d) + 40.0 kJ
88 - In one or more of the following molecules the centra1 atom does
(do) not follow the octet rule:
(1) H2S
(2) BCl3 (3) PH3
**(a) 2, 4 (b)
2 only
(4) SF4
(c)
4, 1 (d)
2, 3
89- Increasing bond order between two atoms:
1) Increases bond energy and increases vibrational frequency.
2) Increases bond energy and decreases vibrational frequency.
3) Increases bond energy and increases bond length.
4) Increases bond energy and decreases bond length.
(a)
1,3
**(b)
1,4
(c) 2,3
١٨
(d)
2,4
........................................................................................................................
90- Intermolecular forces in solid hydrogen are:
(a) Electrostatic forces.
(b) Hydrogen bonds.
**(c) van der Walls forces.
(d) Metallic bonds.
91- The boiling point of water is 100oC whereas that of hydrogen
sulphide is -420C. This can be attributed to:
(a)
H2O molecules has smaller van der Walls forces than H2S
molecules.
(b) Smaller size of oxygen atom as compared to sulpher atom.
(c) H2O molecules form stronger covalent bonds than H2S
molecules
**(d) Larger tendency of H2O to form hydrogen bonds than H2S.
92- Dipole-dipole attractive forces are strongest between molecules
of:
(a)
H2
(b)
CH4
**(c) H2O (d)
CO2
93- The strength of London forces for non-polar molecules F2, C12,
Br2 increases in the following order:
(a)
(c)
C12 > F2 > Br2
Br2 > F2 > C12
**(b) Br2 > C12 > F2
(d) Br2 = F2 = C12
94- Which of the following compounds has the least tendency to form
hydrogen bond between molecules?
(a)
NH3 (b)
NH2OH
**(c) H2S (d)
١٩
HF
95- Which of the following statements is correct:
**(a) London forces oscillate on and off very rapidly.
(b) Helium and hydrogen gases are polar molecules.
(c) Intermolecular attraction forces are much stronger than the
intramolecular attraction forces.
(d) Hydrogen bond is a strong dipole-induced dipole attraction
occurs between molecules.
96- One or more of the following molecule(s) possess(es) dipoledipo1e intermolecular attractive forces:
1) BCl3 2) SO2
3) CO2 4) H2S
(a)
1,3
(b)
1,4
**(c) 2,4
(d)
Only 2
97- One or more of the following molecules has London Forces
only.
(1) +KBF-4
(2) PCl5 (3) NH+4 PF-6 (4) CH4
(a) 4 only
**(c) 2, 4
(d)
(b) 1, 3
All of them
98- The boiling and melting points of HF are higher than those
of HI, because:
(a) HF has stronger covalent bonds.
(b) HI has London forces only.
**(c) HF has hydrogen bonding.
(d) The above statement is not correct.
99- One of the following indicates the presence of weak
intermolecular forces in a liquid:
(a)
A high heat of vaporization.
**(b) A high vapour pressure.
(c)
(d)
A high boiling point.
None of the above.
٢٠
100- One or more of the following properties will decrease by an increase
in the strength of intermolecular forces:
1) Vapour pressure
2) Normal boiling points
3) Normal melting point 4) Heat of vaporization
(a)
2 and 3
**(b)
1 only
(c)
4 only
(d) 1
and 4
101- which statement is true about London forces?
(a) Their strength decreases as molecular size increases.
(b) They are not present in all substances
(c) They are about as strong as hydrogen bonds.
**(d) They depend on the ease with which the electron clouds
are distorted (polarized).
102- which statement is incorrect?
(a) London forces are stronger in I2 than in C12.
**(b) Hydrogen bonding always occurs in compounds in
which hydrogen is covalently bonded to a nonmetal.
(c) The total strength of the London forces is larger in
C8H18 than in C3H8.
(d) Intermolecular attractions are much weaker than
intramolecular attractions.
103Which of the following substances would be expected to have
the largest heat of vaporization?
(a)
PH3 (b)
HBr
(c)
H2S **(d) H2O
104- H2NCH2CH2NH2 (1) and CH3CH2CH2NH2 (II) are similar
compounds in size and molecular weight. How their boiling
points compare:
**(a) I is higher than II
(b)
٢١
I is the same as II
(c) I is less than II
(d) No enough information’s
……………………………………………………………………..
105- Lewis acid-base pair is:
(a)
(c)
Cu2+, PF5
NH3, PF5
**(b) Cu2+, F
(d) NH3 , F-
-
106- The conjugate acids of H-, H2O, HS-, and H2AsO4 are:
(a) OH-, OH-, H2S and H3AsO4
(b) H2, H3O+, S- and HAsO42(c) OH-, OH-, S2- and HAsO42**(d)
H2, H3O+, H2S and H3AsO4
107- The following reaction
Cu2+ + 4 NH3
→
[Cu(NHl3)4]2+
(a) Is an oxidation-reduction reaction
(b) Is a Bronsted-Lowry acid base reaction
**(c) Is a Lewis acid-base reaction
(d) None of the above
108- One of the following acts as a base in aqueous solutions:
(a)
SO2 **(b) BaO
(c)
N2O3 (d) CH3OH
109- Which of the following is the strongest acid in aqueous solution?
(a)
H3PO3
HC1O4
(b)
H2SO4
(c)
HClO3
**(d)
110- Which of the following species : Zn2+, H+, BF3 could be a Lewis
acid?
(a)
(c)
Only Zn2+
Only H+
(b) Only BF3
**(d) All of the above
٢٢
111- In each of the following pairs choose the compound that
leads to the more acidic solution:
(a)
(c)
HBr, HF
HBr
HNO2, HNO3 HNO3
(b)
(d)
PH3, H2S H2S
H2SO3, H3BO3 H2SO3
112- Write the formula for the conjugate base of each of the
following:
(a)
(c)
HI
PH4+
IPH3
(b)
(d)
NO2SO42-
HNO2
HSO4-
113- One of the following statements is incorrect:
(a)
in the Lewis theory, a base can donate its electron
pair to something other than H+.
(b) Lewis acids include molecules with an incomplete
octet of electrons.
(c) Many simple cations can function as Lewis acids.
**(d) Not everything that is a base in the Bronsted-Lawry
theory is also a base in the Lewis theory
114- The formula of the conjugate base of HPO42- is
(a)
H2PO4-
**(b)
PO43-
(c)
PO33- (d)
H3PO4
115- In water, the acid HNO3 is stronger than H2CO3, thus the
strongest base is:
(a)
H3O+ (b) NO3-
**(c) HCO3-
(d) H2O
116- In the following reaction:
NO+ + H2O → H+ + HNO2
Which serves as Lewis acid.
(a)
HNO2
(b) H2O
(c)
٢٣
H+
**(d) NO+
117- Which of the following is not true about Lewis acid-base
reactions?
(a)
(b)
A Lewis base supplies a Pair of electrons to a Lewis acid.
Electron deficient molecules such as BCl3 tend to be
Lewis acids.
(c) A coordinate covalent bond is formed when a Lewis
acid reacts with a Lewis base.
**(d) Water is a product in any Lewis acid-base reaction.
118- Which is the strongest of these oxo-acids?
(a) H2SO3
H2CO3
**(b)
HClO3
(c)
HBrO3
(d)
119One or more of the following do(es) not represent an acidbase conjugate pair (s):
1)
3)
H2O/OHH3O+/H2O
(a)
1 only
2)
4)
NH4+/NH2H2SO4/SO42-
**(b) 2, 4
(c)
1, 3 (d)
3, 4
16- One of the following is considered neither a Lewis base nor a
Lewis acid:
(a)
BH3 **(b) CH4
(c)
NH3 (d)
H2O
120- The conjugate acid of [S2-] is:
(a)
H2S **(b) HS-
(c)
H2SO4
(d) H2SO3
121Which of the following arrangement is correct as far as the
strength of acidity is concerned?
(a) HClO3 < HBrO3 < HIO3
(b) (b) HClO3 = HBrO3 < HIO3
(c) HIO3 > HBrO3 < HClO3
**(d) HIO3 < HBrO3 < HC1O3
٢٤
122- Which of the following pairs is Lewis acids?
(a)
(c)
BF3 and NH3
CO2 and OH-
**(b) CO2 and BF3
(d) Na2O and NH3
123Which of the following statements is not correct regarding
Lewis acids and bases?
(a)
(b)
NH3 and H2O both behave as Lewis bases.
Substances, which can donate a pair of electrons, are
called Lewis bases.
(c) All Lewis bases are also Bronsted bases.
**(d) Lewis bases must contain an atom having less than
an octet of electrons.
……………………………………………………………………………
124- For the following reaction:
2 NO2 (g)
N2O4 (g) + 57.2 kJ
The amount of product can be increased by
1-
Raising the temperature.
234-
Increasing the total pressure.
Lowering the temperature.
Adding a catalyst.
(a)
1,2
**(b) 2,3
(c)
3,4
125- For the following reaction:
H2 (g) + I2 (g)
(d)
2,4
2 HI (g)
If the equilibrium concentrations are:
[H2] = 0.42 M, [I2] = 0.42 M, [HI] = 3.16 M, the equilibrium
constant Kp is:
**(a) 56.60
(c) 17.91
(b)
(d)
0.0177
1.77
126- If Kc is 0.105 L2/mol2 at 472oC for the reaction
N2(g) + 3H2(g)
2NH3(g)
Then Kp is equal to:
٢٥
(a) 5.25 x l0-4
**(c) 2.81 x l0-5
(b)
(d)
1.55 x 102
3.73 x 102
127- The reaction;
N2O4(g)
2NO2(g) ∆H = 58 kJ
is endothermic from left to right. The reaction will proceed to the left if
we:
(a) Increase the temperature and decrease the volume.
(b) Increase the temperature and remove NO2.
(c) Decrease the temperature and add N2O4.
**(d) Decrease the temperature and add NO2.
128- For the reaction:
H2(g) + CO2(g)
H2O(g) + CO(g), ∆H = +41 kJ
increase in temperature and addition of CO2 will result in:
**(a) Shifting the equilibrium to the right.
(b) Shifting the equilibrium to the left.
(c) Does not affect the reaction equilibrium.
(d) None of the above.
129Which of the following reactions are shifted towards products
on increasing total pressure?
1)
2)
3)
4)
H2 (g) + I2
2HI (g)
CO (g) + Cl2 (g)
COCl2 (g)
N2O4 (g)
2NO2(g)
SO2 (g) + 1/2O2 (g)
SO3
(a) 1,2
**
(c) 2,4
(b)
(d)
2,3
3,4
130- Consider the following equilibrium:
2NO2 (g);
N2O4(g)
٢٦
∆Ho =58 kJ
In what direction will the equilibrium shift when the total
pressure increases by adding N2(g) and the temperature
decreased:
(a) There is no shift in the position of equilibrium.
(b) The equilibrium shifts to the right.
**(c) The equilibrium shifts to the left.
(d) The information given is not enough to tell.
131- For the reaction
2NO(g), the equilibrium
N2(g) + O2(g)
Constant is Kc and for the reaction
½N2(g) + ½O2(g)
NO
the equilibrium constant is Kc then the relationship between Kc
and Kc is:(a) Kc = Kc2
**(c) Kc2 = Kc
(b) Kc = Kc
(d) Non of the above
132- For the following reaction
COCl2 (g)
CO (g) + Cl2 (g)
-3
Kc = 4.6x10 M at 800 K. The value of Kp equals
**(a) 3.02x10-1 atm.
(c) 7x105 atm
(d)
(b) 4.6x10-3 atm.
2.3x10-3 atm
133- For the reaction
I2(g) + Br2(g)
2IBr(g)
Kc = 1.2x10 at a certain temperature. If the initial
concentrations of I2(g) = Br2(g) = 0.15 M. Then the equilibrium
concentrations of I2(g), Br2 (g) and IBr (g) are respectively:
2
(a)
(c)
0.05, 0.05, 0.1
0.023, 0.023, 0.127
**(b) 0.023, 0.023, 0.254
(d) 0.01, 0.01, 0.12
134- For the reaction
CO2(g) + C(graphite)
2CO(g), ∆Ho = +172.5 kJ
٢٧
which of the following more favorable (shifts) to the formation of
carbon monoxide?
(a) Increasing total pressure.
**(c) Increasing temperature.
(b)
(d)
Adding catalyst.
None of the above.
135- If Kc for the following reaction at 927oC
CH4 (g) + H2O (g)
CO (g) + 3H2 (g)
-2
equals 3.92 M , then Kp at the same temperature is:
**(a) 4.04x10-4 atm-2
(c) 6.04x10-2 atm-2
(b)
(d)
1.50x10-5 atm-2
3.65 x 10-10 atm-2
136- For the following reaction
2NH3 (g)
N2 (g) + 3H2 (g)
-5
2
-2
If Kc = 2.6x10 mol L at 127oC. Then Kp at the same
temperature is:
(a)
(c)
2.6x10-5 atm2
8.2x10-4 atm2
**(b) 2.8x10-2 atm2
(d) 2.1x10-3 atm2
137- Hydrogen iodide, HI, decomposes at 400oC according to the
equation:
2HI (g)
H2 (g) + I2 (g)
when 4.0 mol HI was placed in a 5.0 L vessel at 400oC, the
equilibrium mixture was found to contain 0.442 mol I2. The value
of Kc for this reaction at 400oC is:
(a)
(c)
1.30x103
6.23x102
**(b) 2.01x10-2
(d) 3.91x10-1
138- For the following reaction at equilibrium:
N2H4(g)
N2(g) + 2H2(g), ∆H = - 95 kJ
Which of the following shift(s) the reaction towards products:
1)
2)
3)
Addition of catalyst.
Raising temperature.
Lowering temperature.
٢٨
4)
Increasing volume of the container.
(a)
1, 2 (b)
1, 3
(c)
3 only
139- Kc = 4 for the following reaction
acid + alcohol
**(d)
3, 4
ester + water
If we start with initial concentrations of ester and water equal to 0.3
mol L-1. Then the equilibrium concentrations of acid and alcohol are
respectively.
**(a) 0.1, 0.1
(c) 0.2, 0.2
(b)
(d)
0.15,0.15
0.25, 0.25
140- The equilibrium constant, Kc for the reaction:C(S) + CO2(g)
2CO(g) equals:**(a) [CO]2/[C][CO2]
(c) [CO]2/[CO2]
(b)
[CO]/[CO][CO2]
(d) [CO2]/[CO]2
141- Kp for the reaction:
2A (g) + 3B (g)
2C (g), is:-
(a) P2C / P3B
**(b) P2C / P3B. P2A
(c) P3B.P2A / P2C
(d) P2B / P3C
142- Write the direction of the equilibrium system between brackets
for this reaction 2SO2 (g) + O2 (g)
2SO3 (g) + heat
(a)
(b)
(c)
When temperature decrease.
When total pressure increased.
Remove SO3(g).
(Right
(Right
)
(Right
)
)
143- For the reaction,
H2(g) + I2(g) = 2HI(g),
When the pressure is increased the position of equilibrium will be
shifted to:
(a) Right
(b)
Left
**(c) No effect
٢٩
144- Knowing that: [NO] = 0.01 M, [C12] = 0.01 M, [NOCl] = 0.02 M
for the reaction,
2 NO(g) + Cl2(g) = 2NOCl. So Kc is:
**(a) 400
(b)
200
(c)
0.0025
………………………………………………………………………………
145- A solution of 5 grams isopropyl alcohol C3H7OH in water has a
mole fraction of alcohol equal to 0.25. The molality of this
solution would be:
(a)
(c)
4.2 m
29.7 m
(b) 12.0 m
** (d)
18.5 m
146- One or more of the following properties will decrease by an increase
in the strength of intermolecular forces:
1)
2)
3)
4)
Vapour pressure.
Normal boiling points.
Normal melting point.
Heat of vaporization.
(a)
(c)
2 and 3
4 only
**(b) 1 and 2
(d) 1 and4
147- An aqueous concentrated nitric acid is 70.7% HNO3 by weight.
The density of the solution is 1.42 g/mL. What is the molarity of
the HNO3?
(a)
(c)
17.3 M
12.3 M
**(b) 15.9 M
(d) 14.1 M
148- The number of grams of NaCl that have to be dissolved in 500 g
of H2O to form an aqueous 0.150 m solution are: (m = molality)
**(a) 4.39 g of NaCl
(b)
٣٠
8.77 g of NaCl
(c)
2.l9 g of NaCl
(d)
17.50 g of NaCl
149Concentrated HCl is 36% (w/w). The density of the solution is
1.19 g/mL. The molar concentration of HCI is:
**(a) 11.7 M
(c) 10 M
(d)
(b) 1 M
None of the above
150- A mole fraction of CaCl2 and water respectively in a solution that
has a CaCl2 concentration of 4.57 m is:
(a)
(c)
0.508, 0.538
0.095, 0.911
**(b) 0.076, 0.924
(d) 0.456, 0.552
151- What is the approximate boiling point of an aqueous 0.75 m
(NH4)2SO4 solution (kb = 0.51 oC/m)
(a)
(c)
l00.38oC
102.68oC
**(b) l01.15oC
(d) 105.74oC
152- Which one of the following statements is false?
(a)
(b)
∆Hsoln. = 0 for an ideal solution.
Gases become less soluble in a liquid solution as the
temperature of the solution is raised.
(c) In an ideal solution of substances A and B, the A-A, B-B and
A-B attractive forces are all equal.
**(d) Solids normally become much more soluble in liquids as the
pressure is increased.
153- If an aqueous solution is 0.273 m KCl, then molar concentration
is (density of solution is 1.011 gmL-1)
(a)
(c)
0.273 M
0.276 M
**(b) 0.271 M
(d) 0.250 M
٣١
154- A solution was prepared by mixing 50.00 mL of 0.100 M HNO3
and 100.00 mL of 0.200 M HNO3. The molarity of the final
solution of HNO3 is:
(a)
(c)
0.210 M
0.021 M
(b) 0.150 M
**(d) 0.167 M
155- If the weight percent of formic acid in an aqueous solution is 5.011%
and its solution density is 1.009 g/mL, then its molarity is:
(a) 1.15 M
**(c) l.099M
(b)
(d)
l.115 M
l.005 M
156- Deviation from Raoultts law is observed in:
(a)
(b)
(c)
Ideal solutions
In all types of solutions
Only when intermolecular forces of attractions between the
components are weak
**(d) When ∆Hsoln is non-zero
157For a solid dissolving in a liquid. if the lattice energy of the
solid is larger than the solvation (hydration) energy of its particles, then
(a) None of the solid can dissolve in the solvent.
(b) An ideal solution will be formed.
**(c) ∆H solution will be endothermic.
(d) ∆H solution will be exothermic.
158- When 33.3 g of C2H5OH are added to 76.7 ml of water, the
resulting solution occupies a volume of 105 ml. What is the
molarity of the solution?
(a) 33.3 M
**(c) 6 89 M
(b)
(d)
٣٢
7.23 M
9.42 M
159Concentrated HCl is 38% (w/w) HCl in water. How many
grams of HCl are there in 25 g concentrated HCl?
(a)
(c)
38.09
25.5
(d)
**(b) 9.5
12.0
160- The best conditions for dissolving CO2 gas in water are:
(a) High pressure and temperature
(b) Low pressure and temperature
**(c) High pressure and low temperature
(d) Low pressure and high temperature
161- A solution is prepared by dissolving 0.5842 g oxalic acid
(H2C2O4) in enough water to make 100.0 mL of solution. A 10.0
mL of the above solution is then diluted to a final volume of'
250.0 mL. The final molarity of the solution is:
(a)
(c)
6.488X10-2 M
3.244 x 102 M
(b) 1.300X10-3 M
**(d) 2.595x10-3 M
162- Vinegar is an aqueous 5.0% acetic acid (CH3COOH), solution by
mass. If the density of vinegar is 1.01 g/mL, then the mole
fraction, molarity, molality of the solution respectively, are:
(a)
(c)
0.008, 0.435, 0.42
0.032, 1.74, 1.68
**(b) 0.016, 0.87, 0.84
(d) 0.019, 0.99, 0.94
163- An aqueous solution of 15 molal CH3OH. What is the percent by
weight of CH3OH in this solution?
**(a) 32.4%
(c) 480%
(b)
(d)
27.6%
15.0%
164- The molality of 1.0 g of phenol (C6H5OH) in 50 g of H2O is:
(a)
(c)
2.13x10-4 m
0.341m
(d)
٣٣
**(b) 0.213m
0.02m
165- The mole fraction of 14.0% by weight Na2CO3 solution in
water is:(a)
(c)
0.973
0.132
**(b) 0.027
(d) 1.021
166 One of the following aqueous solutions has the highest osmotic
pressure
1) Solution of C6H12O6 (0.01 M)
2) Solution of NaCl (0.01 M)
3)
Solution of CaC12
(a) 1
**(c) 3
(0.01 M)
(b)
(d)
2
not enough information
167- A solution contains 3.75 g of a nonvolatile pure hydrocarbon in
95 g acetone (C3H6O). The boiling points of pure acetone and the
solution are 55.95oC and 56.50oC respectively (kb = l.71 oC/m).
The molar mass of the hydrocarbon is:
(a) 130 g/mol
**(c) 120 g/mol
(b)
(d)
310 g/mol
210 g/mol
168- A 0.002 molal aqueous solution of Co(NH3)4(NO2)2C1 freezes at 0.00744oC. How many moles of ions does one mole of the salt give
on being dissolved? (k1 = 1.86 oC/m).
(a)
(c)
0.5
8
**(b) 2
(d) 3
169- What is the osmotic pressure at 0.0oC of a solution containing
7.08 g non-electrolyte substance dissolved in 100 g water. The
vapour pressure of the solution at 0.0oC is 4.557 mm Hg and for
water is 4.62 mm Hg, density of the solution is 1.0 g/mL.
**(a) 17.2 atm
(c) 166.18 atm
(b)
(d)
٣٤
248.54 atm
2.56 atm
170- In binary solution; X1 and X2 are the mole fraction of the two
components having Po1 and Po2 respectively. The total pressure
above the solution is:
**(a) (Po1 - Po2) X1 + Po2
(b) (Po1 X1 - Po2 X2)
(c) (Po1 + Po2) X2 – X1Po2
(d) (Po2 - Po1) X2 – (Po1 –Po2)X1
171- A solution containing 1 g of solute per 100 g of benzene freezes
at 0.4oC lower than pure benzene. Calculate the molar mass of the
solute, (g/mol). (kf = 5.12 oC/m)
(a)
(c)
204.8
180.0
**(b) 128.0
(d) 20.4
172- When a non-volatile substance is dissolved in water
**(a) The freezing point of the solution will be lowered.
(b) The boiling point of the solution will be lowered.
(c) The vapour pressure of the solution will be increased.
(d) Both the freezing point and boiling point are increased.
………………………………………………………………………………
173- Increasing the pH of a solution from 8 to 11 requires:
(a) Increasing [H+] 3 times its original concentration.
(b) Decreasing [H+] 3 times its original concentration.
(c) Increasing [H+] 1000 times its original concentration.
**(d) Decreasing [H+] 1000 times its original concentration.
174- The pOH of 0.5 M HCI is:
(a)
1.0
(b)
13.0
(c)
0.3
**(d) 13.7
175- The following aqueous mixture(s)
solution(s):
1- Acetic acid / sodium acetate
2- NH3 / NH4Cl
3- NH3 / NaOH
٣٥
form(s)
acidic buffer
4-
Acetic acid / NaCl
(a)
(c)
1,2
1,4
**(b) Only 1
(d) 2,4
176- The pH of a 0.20 M solution of HCN, (Ka = 4.9 x 10-10) is:
(a)
(c)
3.41
6.25
**(b) 5.0
(d) 2.83
5- The pH of a solution that is made by dissolving 0.4 g of NaOH in 1 L
of solution is:
(a)
7
(b)
**(c) 12
2
(d)
5
177- What is the pH of a 0.010 M solution of Ba(OH)2? [Ba(OH)2 is a
strong base.
(a) 4.4
(b) 7.0
(c) 12
**(d) 12.30
178- what is the pH of a 0.0037 M solution of H2CO3? H2CO3 is a weak
acid with Ka = 4.3x10-7
**(a) 4.4
(b)
2.8
(c)
8.5
(d)
7.0
179- The pH of an aqueous 0.1 M weak base is 11. Then Kb for the
base is:
(a)
lx10-11
**(b)
1x10-5
(c)
1x10-6
(d) 1x10-3
180- The concentration of HCl having the same pH as that of 0.1 M
HC2H3O2 (Ka = 1.8x10-5) is:
(a)
(c)
0.1 M
1.8x10-5M
(b) 0.01 M
**(d) 1.34x10-3M
181- The pH of 2.9x10-4 M aqueous HNO3 solution is
٣٦
(a)
(c)
1.30
9.50
(b) 7.65
**(d) 3.54
182- A solution that is 0.012 M in nicotinic acid, HC6H4NO2, has a pH
of 3.39 at 25oC. The acid-ionization constant, Ka, at 25oC is:
(a)
(c)
1.9x10-5
4.8x10-4
**(b) 1.4x10-5
(d) 6.8x10-4
183- Changing the pH of a solution from 5 to 1 causes:
(a) Increase in [H+] by 4 times
(b) Decrease in [H+] by 4 times.
(c) Increase in [H+] by 106 times.
**(d) None of the above.
184- The ratio between [H+] in a 0.1 M HCl (aq) and 0.1 M HC2H3O2
(Ka(HC H O ) = 1.8xl0-5) is;
2
3
2
(a) 1: 1
**(c) 75: 1
(b)
(d)
10: 1
90: 1
185- In an aqueous solution of NH3 the concentration of [OH-](aq)
is 1.8x10-3 M, Kb = 1.8x10-5, the concentration of NH3 will be:(a)
(c)
1.34x10-4 M
1.8x10-4 M
(d)
**(b) 0.18 M
1.34M
186- The H+ concentration in a solution having a pH of 13 is:
(a) 1.0x10-14 M
**(c) 1.0xl0-13M
(d)
(b) 1.0xl0-7 M
1.0xl0-11M
187- What are the [H+] and [OH-] for a solution having pH = 4.0
**(a) [H+] =
10-4,
(b) [H+] = 10-10,
(c) [H+] = [OH-] = l0-4
(d) [H+] = [OH-] = l0-7
[OH- ] = 10-10
[OH-] = 10-4
٣٧
188- The concentration of H+(aq) corresponds to pOH =3.33 is:**(a) 2.14x10-11
(c) 1x10-14
(b)
4.68x10-10
(d) 3.68x10-13
189- The pH of a buffer solution of 0.1 M NH3 and 0.1 M NH4Cl is:
(Kb = l.8x10-5)
(a)
(c)
13
4.74
**(b) 9.26
(d) 7.44
190The pH of an HCl solution is 4.65. How many moles of HCl
are in 450 mL at of this solution?
**(a) 1xl0-5 mol
(c) 4xl0-5mol
(b) 6 xl0-6 mol
(d) 5xl0-5 mol
191- At the normal human body temperature (37oC) the ion product
constant for water, Kw has a value of 2.42x10-14. What is the pH of a
neutral solution at this temperature?
(a)
7.2
(b)
13.6
(c)
7.0
**(d) 6.8
192- The pH of 0.2 M aqueous solution of NaOH is
(a)
0.2
(b)
2.0
(c)
7.0
**(d) 13.3
193- The OH- concentration in a solution having a pH of 9.0 is:
(a) 1.0x10-9 M
**(c) 1.0xl0-5 M
(b)
(d)
1.0x10-7 M
1.0x10-3 M
194- What is the [OH-] of 0.3 M NH3 solution? (Kb = 1.8x10-5)
(a) 11.366
**(c) 0.0023
(b)
(d)
٣٨
2.634
5.482
195- What are the concentrations of H+ and OH- respectively in a 0.04
M solution of HNO3?
**(a) 0.04, 2.5x10-13
(c) 0.04, 2.5
(b)
(b) 1.4, 12.6
1.4, 12.6x10-8
196- The concentrations of H+(aq) and OH-(aq) in a 0.015 M solution
of HNO3 are:
**(a) 0.0l5 M and 6.7x10-13 M
(c) lx10-12 M and lxl0-12M
(b)
(d)
0.1 M and 1xl0-13 M
1x10-3 M and lxl0-11 M
197- A 0.26 M solution of a weak acid, HX, has a pH of 2.86, the
ionization constant of the acid, Ka, is
**(a) 7.3x10-6
(c) 1.3x10-9
(b)
(d)
1.8x10-5
1.9xl0-7
198- How much solid NaC2H3O2 (sodium acetate) must be added to lL
of 0.5 M acetic acid to give a buffer with pH = 4.57 (neglect any
volume changes as the solid is added) Ka = 1.8x10-5
(a)
(c)
0.50 mol
0.666 mol
**(b) 0.333 mol
(d) l0mol
199- If 0.1 mol of NaOH is added to the above buffer then the new pH
is:
**(a) 4.78
(c) 4.57
(b)
(d)
4.36
5.571
200- In a buffer solution of 0.025 M acetic acid and 0.001 M of sodium
acetate solution; the pH of the solution will be:- (Ka = 1.8x10-5)
(a) 6.14
**(c) 3.342
(b)
٣٩
4.74
(b) 2.49
201- The pH of the buffer prepared by adding 0.2 mol of acetic acid
and 0.4 mol of sodium acetate in 1.0 dm3 water is: (Ka =
1.8x10-5)
(a)
8.96 (b)
4.44
**(c) 5.05 (b)
3.61
202- If the pH of a buffer composed of 0.1 M weak acid and 0.1M of
its sodium salt is 4.5, then Ka of the acid is:
(a) lxl0-5
(b) 1.8xl-5
**(c) 3.16x10-5
(d) lxl0-6
203- A buffer mixture composed of 0.9 M NH3(aq) and 0.3 M
NH4C1(aq). If 0.1 mol HCl was added to l L of the buffer, then the
new pH: ( Kb = 1.8xl0-5 )
**(a) 9.56
(c) 4.04
(b)
(d)
9.95
4.44
204- The pH of a buffer solution of 0.1 M CH3COOH and 0.01 M
CH3COONa is: (Ka = 1.8x10-5)
(a) 7
**(c) 3.74
(b)
(d)
10.3
5.5
205- What concentration ratio should be used to prepare a benzoic
acid-benzoate ion buffer with a pH of 5.0? (Ka = 6.0x10-5).
(a)
(c)
6
6.0x10-5
**(b) 0.167
(d) 1.67
206- 0.05 M of Formic acid containing an unknown conc. of formate
ion derived from sodium formate has a pH of 3.8. What is the
concentration of formate ion in the solution? (Ka = 1.8x10-4)
(a)
(c)
0.0435 M
0.025M
**(b) 0.057 M
(d) 0.002 M
٤٠
207The concentrations ratio which should be used to prepare an
ammonia / ammonium ion buffer
[NH3]
[NH4+]
(a)
(c)
1.0
0.56
with a pH of 9.5 are: (Kb = 1.8x10-5)
(b) 0.38
**(d) 1.77
٤١