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Chemistry
Ionic Equilibrium
148 questions · Click an option and press Check Answer to reveal the result
1
Given the following Ka values, determine which species is the strongest base. HSO₄⁻ = 1.2 × 10⁻², H₂PO₄⁻ = 6.3 × 10⁻⁸, HCO₃⁻ = 4.7 × 10⁻¹¹
A
CO₃²⁻
B
H₂SO₄
C
SO₄²⁻
D
HPO₄²⁻
2
Addition of sodium acetate solution to acetic acid causes the following change–
A
pH increases
B
pH decreases
C
pH remains unchanged
D
pH becomes 7
3
Four solutions of NH₄Cl are taken with concentrations 1 M, 0.1 M, 0.01 M and 0.001 M. Their degree of hydrolysis are h₁, h₂, h₃ and h₄. What is the gradation of degree of hydrolysis ?
A
h₁ > h₂ > h₃ > h₄
B
h₁ = h₂ = h₃ = h₄
C
h₄ > h₃ > h₂ > h₁
D
None of these
4
At 298K, the solubility of PbCl₂ is 6.3×10⁻³ moles L⁻¹. Its solubility product at this temperature is –
A
(6.3 × 10⁻³) × (6.3 × 10⁻³)
B
(6.3 × 10⁻³) × (12.6 × 10⁻³)
C
(6.3 × 10⁻³) × (12.6 × 10⁻³)²
D
(12.6 × 10⁻³) × (12.6 × 10⁻³)
5
The salt of which of the following four weak acids will be most hydrolysed –
A
HA ; Ka = 1 × 10⁻⁸
B
HB ; Ka = 2 × 10⁻⁶
C
HC ; Ka = 3 × 10⁻⁸
D
HD ; Ka = 4 × 10⁻¹⁰
6
Consider the following two statements for the given equilibrium
Fe³⁺(aq) + SCN⁻(aq) ⇌ [Fe(SCN)]²⁺(aq)
Statement I: Addition of oxalic acid will shift equilibrium to the left side.
Statement II: Addition of aqueous HgCl₂ decreases the intensity of red colour.
In the light of above statements, choose the most appropriate answer from the options given below.
A
Both statement I and statement II are correct.
B
Both statement I and statement II are incorrect.
C
Statement I is correct but statement II is incorrect.
D
Statement I is incorrect but statement II is correct.
7
Approximate pH of 0.01 M NaHA is calculated by : (Ka₁ = 10⁻⁶ and Ka₂ = 10⁻⁸ are ionization constants of H₂A)
A
pH = 7 + pKa₁/2 + logC/2
B
pH = 7 − pKa₁/2 − logC/2
C
pH = (pKa₁ + pKa₂)/2
D
None of these
8
Equal volumes of 0.005 M and 0.005 N H₂SO₄ solutions are mixed together. The pH of resulting solution is –
A
5.0
B
3.125
C
4.1
D
2.125
9
Acetic acid (Ka = 2 × 10⁻⁵) and propionic acid (Ka = 2 × 10⁻⁶) have same concentrations. What is the ratio of their degree of ionisation
A
100
B
√10
C
10
D
0.1
10
Which of the following is a buffer solution ?
A
500 mL of 0.1 N CH₃COOH + 500 mL of 0.1 N NaOH
B
500 mL of 0.1 N CH₃COOH + 500 mL of 0.1 N HCl
C
500 mL of 0.1 N CH₃COOH + 500 mL of 0.2 N NaOH
D
500 mL of 0.2 N CH₃COOH + 500 mL of 0.1 N NaOH
11
In the neutralization process of H₃PO₄ and NaOH, the number of buffers formed will be -
A
3
B
1
C
2
D
4
12
The solution of blue vitriol in water is acidic because –
A
CuSO₄ reacts with water
B
Cu²⁺ reacts with water
C
SO₄²⁻ reacts with water
D
CuSO₄ removes OH⁻ ions from water
13
Which of the following salts has maximum solubility –
A
HgS, Ksp = 1.6 × 10⁻⁵⁴
B
PbSO₄, Ksp = 1.3 × 10⁻⁸
C
ZnS, Ksp = 7.0 × 10⁻²⁶
D
AgCl, Ksp = 1.7 × 10⁻¹⁰
14
Phenolphthalein shows colour change in a definite pH range, which is-
A
5.5 - 7.4
B
4.5 - 6.5
C
8.3 - 6.5
D
8.3 - 10.5
15
Consider this equilibrium, for which ΔH < 0, HgO(s) + 4I⁻(aq.) + H₂O(ℓ) ⇌ HgI₄²⁻ + 2OH⁻ Which changes will increase the equilibrium concentration of HgI₄²⁻ ? I. Increasing the mass of HgO(s) present II. Increasing [I⁻] III. Adding 1 M HCl
A
I only
B
II only
C
II and III only
D
I, II and III
16
The concentration of a monoprotic acid is C moles L⁻¹ and ionisation constant Ka. The pH of the solution is –
A
½ pKa − ½ log C
B
(Ka × C)½
C
½ pKa + ½ log C
D
α.C
17
H₂CO₃ + NaHCO₃ found in blood helps in maintaining pH of the blood close to 7.4. An excess of acid entering the blood stream is removed by-
A
HCO₃⁻
B
H₂CO₃
C
H⁺ ion
D
CO₃²⁻ ion
18
What is the minimum concentration of SO₄²⁻ required to precipitate BaSO₄ in a solution containing 1.0 × 10⁻⁴ mole of Ba²⁺ ? Ksp for BaSO₄ = 4 × 10⁻¹⁰ :
A
4 × 10⁻¹⁰ M
B
2 × 10⁻⁷ M
C
4 × 10⁻⁶ M
D
2 × 10⁻³ M
19
Which one of the following mixture does not act as a buffer solution-
A
Boric acid and borax
B
Sodium phosphate & disodium hydrogen phosphate
C
Sodium propionate and propionic acid
D
Sodium acetate and sodium propionate
20
In the hydrolysis of sodium acetate –
A
Anions of the salt are hydrolysed
B
Cations of the salt are hydrolysed
C
Both of the above ions are not hydrolysed
D
None of these
21
The colour of phenolphthalein in acid is-
A
Red
B
Yellow
C
Colourless
D
Green
22
At 25°C what will be the solubility of silver carbonate in 0.1 M Na₂CO₃ solution. At this temperature Ksp of silver carbonate is 4 × 10⁻¹³ –
A
2 × 10⁻⁷
B
2 × 10⁻⁶
C
10⁻⁶
D
10⁻⁷
23
The dissociation constants of monobasic acids A,B,C and D are 6 × 10⁻⁴, 5 × 10⁻⁵, 3.6 × 10⁻⁶, and 7 × 10⁻¹⁰ respectively. The pH values of their 0.1 molar aqueous solutions are in the order –
A
A < B < C < D
B
A > B > C > D
C
A = B = C = D
D
A > B < C > D
24
The pH of two solutions are 5 and 3 respectively. What will be the pH of the solution made by mixing equal volumes of the above solutions –
A
3.5
B
4.5
C
3.3
D
4.0
25
The degree of hydrolysis of 0.1 RNH₃Cl solution is 1.0 %. If the concentration of RNH₃Cl is made 0.4 M, what is the new degree of hydrolysis (in percentage) ?
A
0.01
B
0.001
C
0.2
D
0.5
26
The pH of a solution is 6.0. In this solution –
A
[H⁺] = 100 [OH⁻]
B
[H⁺] = 10 [OH⁻]
C
[H⁺] = 1/10 [OH⁻]
D
[H⁺] = [OH⁻]
27
H₃PO₄ is a weak triprotic acid; approximate pH of 0.1 M Na₂HPO₄(aq.) is calculated by -
A
½ [ pKa₁ + pKa₂ ]
B
½ [ pKa₂ + pKa₃ ]
C
½ [ pKa₁ + pKa₃ ]
D
pKa₁ + pKa₂
28
Formula for degree of hydrolysis ‘h’; h = [10⁻⁷ (KaKb)⁻½] is applicable to the salt –
A
NH₄CN
B
(NH₄)₂SO₄
C
NH₄Cl
D
NH₄NO₃
29
Solubility of AgCl [Ksp = 1 × 10⁻¹⁰] in 0.2 M AgNO₃ and 0.2 M NaCl solution will be respectively –
A
5 × 10⁻¹⁰ M and 2 × 10⁻⁵ M
B
5 × 10⁻¹⁰ M and 5 × 10⁻¹⁰ M
C
2 × 10⁻⁵ M and 2 × 10⁻⁵ M
D
5 × 10⁻⁵ M and 5 × 10⁻⁵ M
30
A solution of 0.1 M weak base (BOH) is to be titrated with 0.1 M strong acid (HA) at the half equivalence point the pH is 10.7 what is the pKₐ of base
A
3.3
B
4.7
C
9.3
D
10.7
31
pOH = 7–0.5 pKa + 0.5 pKb is true for which pair of cation and anion.
A
C₆H₅NH₃⁺, CH₃COO⁻
B
Na⁺, CN⁻
C
Al³⁺, Cl⁻
D
NH₄⁺, NO₃⁻
32
Pure water ionises as 2H₂O (ℓ) ⇌ H₃O⁺ (aq.) + OH⁻ (aq) At 25°C the pH of pure water is approximately 7.0 At 37°C its pH is –
A
More than 7.0
B
Less than 7.0
C
Equal to 7.0
D
None of these
33
What concentration of HCOO⁻ is present in a solution of 0.01 M HCOOH (Ka = 1.8 × 10⁻⁴) and 0.01 M HCl ?
A
1.8 × 10⁻³
B
10⁻²
C
1.8 × 10⁻⁴
D
10⁻⁴
34
Kw for water at 25°C is equal to 10⁻¹⁴. What is its value at 90°C –
A
10⁻¹⁵
B
10⁻¹⁷
C
10⁻¹⁴
D
10⁻¹²
35
The necessary condition for saturated solution is
A
Product of ionic concentrations = Solubility product
B
Product of ionic concentrations < solubility product
C
Product of ionic concentrations > solubility product
D
None of the above
36
The concentration of a HCl solution is 10⁻² N. If this solution is diluted ten times then its pH will-
A
Become ten times
B
Become double
C
Increase by one unit
D
Decrease by one unit
37
Will a precipitate form if 50 cm³ of 0.01 M AgNO₃ and 50 cm³ of 2 × 10⁻⁵ M NaCl are mixed ? [Given : Ksp (AgCl) = 10⁻¹⁰ M²]
A
Yes
B
No
C
Ionic product is less than solubility product, hence precipitate will form
D
Data insufficient
38
A monoprotic acid in a 0.1 M solution ionizes to 0.001%. Its ionization constant is –
A
1.0 × 10⁻³
B
1.0 × 10⁻⁶
C
1.0 × 10⁻⁸
D
1.0 × 10⁻¹¹
39
% hydrolysis of 0.1M CH₃COONH₄, when Ka = Kb = 1.8 × 10⁻⁵ is -
A
0.55
B
7.63
C
0.55 × 10⁻²
D
7.63 × 10⁻³
40
A 0.01 M acetic acid solution is 1.0% ionised. An another acetic acid is 10% ionised. What will be the concentration of another acetic acid -
A
0.001 M
B
0.0001 M
C
0.01 M
D
0.1 M
41
Ksp for Pb(IO₃)₂ is 3.2 × 10⁻¹⁴ at a certain temperature. Its solubility will be –
A
3.6 × 10⁻⁷
B
2 × 10⁻⁵
C
4 × 10⁻⁵
D
8 × 10⁻⁵
42
0.01 M Acetic acid is 12.5 % dissociated. Its pH will be –
A
4.509
B
3.723
C
2.903
D
5.623
43
The dissociation constant of a weak acid is 1.0 × 10⁻⁴. The equilibrium constant of its reaction with strong base is –
A
1.0 × 10⁻⁴
B
1.0 × 10⁻¹⁰
C
1.0 × 10¹⁰
D
1.0 × 10⁻¹⁴
44
At 298 K, how many milligrams of silver bromide can be dissolved in 20 litres of water - [Ksp(AgBr) = 5.0 × 10⁻¹³] (Atomic wt. Ag = 108, Br = 80)
A
2.66
B
3.66
C
4.66
D
None of these
45
If pKb > pKa then the solution of the salt of weak acid and weak base will be -
A
Neutral
B
Acidic
C
Basic
D
Amphoteric
46
0.05 M ammonium hydroxide solution is mixed with 0.001 M ammonium chloride solution. What will be the OH⁻ ion concentration of this solution – Kb(NH₄OH) = 1.8 × 10⁻⁵
A
3.0 × 10⁻³
B
9.0 × 10⁻⁴
C
9.0 × 10⁻³
D
3.0 × 10⁻⁴
47
For two weak acids A and B, the ratio of their percent ionization is 4 : 9. The ratio of their Ka would be–
A
4 : 9
B
2 : 3
C
16 : 81
D
3 : 2
48
What will be the pH of 10⁻³ M monobasic weak acid solution if its dissociation constant is 1.8 × 10⁻⁵ –
A
4
B
3.872
C
2.52
D
2.00
49
What is the pH of the solution at half neutralization in the titration of 0.1N CH₃COOH and 0.1N KOH : (Ka = 1.8 × 10⁻⁵)–
A
4.75
B
1
C
13
D
Zero
50
The hydrolysis constant for ZnCl₂ will be -
A
Kh = K²w / K²b
B
Kh = Kw / Kb
C
Kh = Kb / K²w
D
Kh = K²w / Kb
51
What will be the pH and % α (degree of hydrolysis) respectively for the salt BA of 0.1 M concentration ? Given : Ka for HA = 10⁻⁶ and Kb for BOH = 10⁻⁶
A
5, 1 %
B
7, 10%
C
9, 0.01%
D
7, 0.01%
52
For a binary weak electrolyte, the degree of dissociation is proportional to the-
A
Dilution
B
Square root of dilution
C
Concentration
D
Square root of concentration
53
In a buffer solution of a weak acid and its salt, if the ratio of concentration of salt to acid is raised 10 times then pH of the solution will-
A
Increase ten times
B
Decrease by one unit
C
Decrease ten times
D
Increase by one unit
54
The pH of 1 litre solution containing 0.5M NH₄OH and 0.5 M NH₄Cl (pKb = 5) -
A
5
B
9
C
5 ± 1
D
9 ± 1
55
Which of the following acids is stronger than benzoic acid (Ka = 6.3 × 10⁻⁵) -
A
A (Ka = 1.62 × 10⁻⁷)
B
B (pKa = 6)
C
C (pKa = 4)
D
D (Ka = 1.0 × 10⁻⁵)
56
For an acid solution the [OH⁻] is –
A
> 10⁻⁷
B
< 10⁻⁷
C
10⁻¹⁴
D
10⁻⁷
57
A sufficient quantity of acid is added to change its pH from 5 to 2. Its hydrogen ion concentration is increased by –
A
100 times
B
1000 times
C
2.50 times
D
5 times
58
Which one of the following is NOT a buffer solution ?
A
0.8 M H₂S + 0.8 M KHS
B
2M C₆H₅NH₂ + 2 M C₆H₅NH₃⁺ Br⁻
C
3 M H₂CO₃ + 3 M KHCO₃
D
0.05 M KClO₄ + 0.05 M HClO₄
59
Ksp for A₂B salt is 4 × 10⁻⁹. Evaluate its solubility –
A
4 × 10⁻² M
B
2 × 10⁻⁴ M
C
1 × 10⁻⁴ M
D
1 × 10⁻³ M
60
Which of the following expressions shows the saturated solution of PbSO₄ –
A
Ksp (PbSO₄) = [Pb²⁺] [SO₄²⁻]
B
Ksp (PbSO₄) > [Pb²⁺] [SO₄²⁻]
C
Ksp (PbSO₄) = [Pb⁺] [SO₄⁻]
D
Ksp (PbSO₄) < [Pb²⁺] [SO₄²⁻]
61
20 cm³ of xM solution of HCl is exactly neutralised by 40 cm³ of 0.05 M NaOH solution, the pH of HCl solution is :
A
1.0
B
2
C
1.5
D
2.5
62
Methyl Orange is-
A
Acidic indicator
B
Basic Indicator
C
Neutral
D
None of the above
63
A solution contains 0.2 M NH₄OH and 0.2 M NH₄Cl. If 1.0 ml of 0.001 M HCl is added to it. What will be the [OH⁻] of the resulting solution (Kb = 2 × 10⁻⁵)
A
2 × 10⁻⁵
B
5 × 10⁻¹⁰
C
2 × 10⁻³
D
None of these
64
At 298 K, the ratio of number of pure water molecules to number of hydroxyl ions is –
A
1.8 × 10⁻⁹
B
5.55 × 10⁸
C
10⁷
D
6.02 × 10²³
65
The ratio of pH of 0.05 M and 0.005 M H₂SO₄ solutions will be –
A
2 : 1
B
1 : 2
C
1 : 1.5
D
1.5 : 1
66
'a' moles of a monacidic base are dissolved in one litre of the solution. The pH of the solution will be -
A
– log a
B
14 – log a
C
14 + log a
D
– log (14 – a)
67
For a salt of weak acid and weak base [pKa − pKb] would be equal to –
A
2 pH + pKw
B
2 pH − log 10⁻¹⁴
C
2 pH − pKw
D
None of these
68
Ostwald’s dilution law gives satisfactory results for -
A
HCl
B
HNO₃
C
CH₃COOH
D
NaOH
69
The value of pKw at 25°C is -
A
7
B
−14
C
14
D
1 × 10⁻¹⁴
70
When 0.02 moles of NaOH are added to a litre of buffer solution, its pH changes from 5.75 to 5.80. What is its buffer capacity –
A
0.4
B
0.05
C
− 0.05
D
2.5
71
The pKb of dimethylamine and pKa of acetic acid are 3.27 and 4.77 respectively at T(K). The correct option for the pH of dimethylammonium acetate solution is:
A
6.25
B
8.50
C
5.50
D
7.75
72
4.0 g of NaOH and 4.9 g of H₂SO₄ are dissolved in water and volume is made upto 250 ml. The pH of this solution is –
A
7.0
B
1.0
C
2.0
D
12.0
73
The dissociation constant of two weak acids are Ka₁ & Ka₂ respectively. Their relative strength is -
A
Ka₂/Ka₁
B
(Ka₁/Ka₂)^(1/2)
C
Ka₁/Ka₂
D
((Ka₁ × Ka₂)/Ka₁)^(1/2)
74
If s is the molar solubility of Ag₂SO₄, then –
A
3 [Ag⁺] = s
B
[Ag⁺] = s
C
[2Ag⁺] = s
D
[SO₄²⁻] = s
75
The units of ionic product of water (Kw) are –
A
mol⁻¹ L⁻¹
B
mol⁻² L⁻²
C
mol⁻² L⁻¹
D
mol² L⁻²
76
What is the pH of an aqueous solution of ammonium acetate (Ka = Kb = 1.8 × 10⁻⁵) –
A
> 7
B
7.0
C
< 7.0
D
Zero
77
Assertion :- Addition of silver ions to a mixture of aqueous sodium chloride and sodium bromide solution will first precipitate AgBr rather than AgCl.
Reason :- Ksp of AgCl < Ksp of AgBr.
A
If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B
If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.
C
If Assertion is True but the Reason is False.
D
If both Assertion & Reason are false.
78
The dissociation constant of weak acid HA is 4.9×10–8. After making the necessary approximations . Calculate pH in 0.1 M acid
A
1.155
B
2.155
C
3.155
D
4.155
79
K₁ and K₂ are the first and second dissociation constants of oxalic acid. Choose the correct statement –
A
K₂ is equal to K₁
B
K₂ is equal to 1000 times K₁
C
K₂ is equal to 1/1000 times K₁
D
All are correct
80
When HCl gas is passed through a impure saturated solution of common salt, pure NaCl is precipitated because –
A
The ionic product [ Na⁺ ] and [ Cl⁻ ] exceeds the solubility product of NaCl
B
The impurities dissolve in HCl
C
HCl is highly soluble in H₂O
D
The solubility product of NaCl is lowered by the Cl⁻ ions from aqueous HCl
81
Ksp of AgCl is 1 × 10⁻¹⁰. Its solubility in 0.1 M KNO₃ will be –
A
10⁻⁵ moles/litre
B
> 10⁻⁵ moles/litre
C
< 10⁻⁵ moles/litre
D
None of these
82
What will be the pH of the solution, if 0.01 mole of HCl is dissolved in a buffer solution containing 0.03 mole of propanoic acid (Ka = 1.0 × 10–5) and 0.02 moles of salt, at 25ºC
A
3.7
B
4.7
C
5.11
D
6.1
83
The pH of buffer of NH₄OH + NH₄Cl - type is given by -
A
pH = pKb
B
pH = 1/2pKb − 1/2 log [salt]/[base]
C
pH = 14 − pKb − log [salt]/[base]
D
pH = pOH − pKb + [salt]/[base]
84
At 25°C, the solubility product of Ca(OH)₂ is 32 × 10⁻¹². What will be the pOH of its saturated solution at this temperature –
A
3.4990
B
3.3980
C
0.3010
D
None of these
85
Ka₁, Ka₂ and Ka₃ are the three dissociation constants of H₃PO₄. Which of the following is a correct order –
A
Ka₁ > Ka₂ < Ka₃
B
Ka₁ > Ka₂ > Ka₃
C
Ka₃ > Ka₂ > Ka₁
D
None of these
86
The pH of two equimolar weak acids are 3.0 and 5.0 respectively. Their relative strength is –
A
3 : 5
B
5 : 3
C
100 : 1
D
1 : 100
87
Determine the molar solubility of MgF₂ from it's solubility product Ksp = 4 × 10⁻⁹ :
A
10⁻³
B
6.32 × 10⁻⁵
C
2 × 10⁻⁵
D
None of these
88
Which of the following compound forms an aqueous solution which is acidic when compared with water –
A
NaOH
B
K₂CO₃
C
BaCl₂
D
Al₂(SO₄)₃
89
The pKw of water at 50°C is 13.40. An aqueous solution at 50°C has pH = 7. This solution is–
A
Acidic
B
alkaline
C
Neutral
D
Amphoteric
90
At 25°C, the dissociation constants of CH₃COOH and NH₄OH in aqueous solution are almost the same. The pH of a solution of 0.01 N CH₃COOH is 4.0 at 25°C. The pH of 0.01 N NH₄OH solution at the same temperature would be :
A
3.0
B
4.0
C
10.0
D
10.5
91
Consider the following salts. Which one(s) when dissolved in water will produce an acidic solution ? 1. NH₄Cl 2. Al₂(SO₄)₃ 3. NaCN 4. KNO₃
A
2 and 3
B
1 and 2
C
only 3
D
2 and 4
92
Find the percentage ionisation of 0.2 M acetic acid solution, whose dissociation constant is 1.8 × 10⁻⁵
A
0.198
B
0.290
C
0.950
D
None of these
93
How much water must be added to 300 mL of 0.2 M solution of CH₃COOH (Ka = 1.8 × 10⁻⁵) for the degree of ionization (α) of the acid to double ?
A
600 mL
B
900 mL
C
1200 mL
D
1500 mL
94
10⁻² mole of KOH is dissolved in 10 litres of water. The pH of the solution is –
A
12
B
2
C
3
D
11
95
The aqueous solution of which of the following sulphides would contain maximum concentration of S²⁻ ions—
A
MnS (Ksp = 1.1 × 10⁻²¹)
B
ZnS (Ksp = 1.1 × 10⁻²³)
C
PbS (Ksp = 1.1 × 10⁻³⁵)
D
CuS (Ksp = 1.1 × 10⁻³⁰)
96
At 30°C, the solubility of Ag₂CO₃ (Ksp = 8 × 10⁻²) will be maximum in –
A
0.05 M Na₂CO₃
B
0.05 M AgNO₃
C
Pure water
D
0.05 M NH₃
97
Which of the following salts will given highest pH in water ?
A
KCl
B
NaCl
C
Na2CO3
D
CuSO4
98
Arrange in increasing order of solubility of AgBr in the given solutions.
(i) 0.1 M NH3 (ii) 0.1 M AgNO3 (iii) 0.2 M NaBr (iv) pure water
A
(iii) < (ii) < (iv) < (i)
B
(iii) < (ii) < (i) < (iv)
C
(iii) < (ii) = (i) < (iv)
D
(ii) < (iii) < (iv) < (i)
99
Which of the following would increase the solubility of Pb(OH)₂–
A
Add hydrochloric acid
B
Add a solution of Pb(NO₃)₂
C
Add a solution of NaOH
D
None of the above–the solubility of a compound is constant at constant temperature
100
How many moles of HCl must be removed from 1 litre of aqueous HCl solution to change its pH from 2 to 3 -
A
1
B
0.02
C
0.009
D
0.01
101
Expression pKh = pKw − pKa − pKb is not applicable to –
A
Ammonium acetate
B
Ammonium cyanide
C
Aniline acetate
D
Ammonium chloride
102
According to Modern quinoid theory the indicator used in acid-alkali titrations are-
A
Aliphatic organic compounds
B
Aromatic organic compounds
C
Inorganic acids
D
Inorganic bases
103
Ostwald’s dilution law for a weak acid HA may be given as –
A
Ka = α.c/(1−α)c
B
Ka = α².c/(1−α)
C
Ka = ((α²)/(1−α))².c
D
Ka = α².c/(1−α²)
104
Calculate the solubility of silver phosphate (Ag₃PO₄) in 0.10M AgNO₃ ? Ksp = 1.1 × 10⁻¹⁶ –
A
0.10 M
B
4.1 × 10⁻¹⁵ M
C
1.1 × 10⁻¹⁵ M
D
1.1 × 10⁻¹³ M
105
pH range of colour change for methyl orange indicator is-
A
6.2 - 7.6
B
4.0 - 5.6
C
3.2 - 4.4
D
9.4 - 10.6
106
H⁺ ion concentration of water does not change by adding –
A
CH₃COONa
B
NaNO₃
C
NaCN
D
Na₂CO₃
107
An aqueous solution of aluminium sulphate would show –
A
An acidic reaction
B
A neutral reaction
C
A basic reaction
D
Both acidic and basic reactions
108
The solubility product of chalk is 9.3 × 10–8. Calculate its solubility in gram per litre
A
0.3040 gram / litre
B
0.0304 gram / litre
C
2.0304 gram / litre
D
4.0304 gram / litre
109
The [H⁺] of a solution is 0.03 M. The pOH of this solution is –
A
12.48
B
10.48
C
9.48
D
13.48
110
The pH of 0.001M sodium acetate solution is [Ka(CH₃COOH) = 1.8 × 10⁻⁵] –
A
≈ 11
B
≈ 6.5
C
≈ 14
D
≈ 8.0
111
What will be the hydrogen ion concentration (moles L⁻¹) of 0.01 M HCN solution if it is 20% ionised
A
0.002 M
B
0.02 M
C
0.2 M
D
0.1 M
112
A solution contains 10 ml of 0.1 N NaOH and 10 ml of 0.05 N Na₂SO₄. pH of this solution is-
A
7
B
Less than 7
C
Greater than 7
D
Zero
113
Which salt can furnish H⁺ in its aqueous solution ?
A
NaH₂PO₂
B
Na₂HPO₃
C
Na₂HPO₄
D
All of these
114
Given the two concentration of HCN are 0.1 M & 0.001 M respectively. What will be the ratio of degree of dissociation -
A
1
B
0.1
C
0.003
D
0.01
115
Which of the following is an acidic salt –
A
Na₂SO₄
B
Ca(OH)Cl
C
Pb(OH) Cl
D
Na₂HPO₄
116
A basic buffer solution can be prepared by mixing the solution of –
A
Ammonium chloride and Ammonium acetate
B
Ammonium acetate and acetic acid
C
Ammonium chloride and ammonium hydroxide
D
Ammonium cyanide and Ammonium hydroxide
117
[H⁺] = √(KwKa/C) is suitable for –
A
NaCl, NH₄Cl
B
CH₃COONa, NaCN
C
CH₃COONa, (NH₄)₂SO₄
D
CH₃COONH₄, (NH₄)₂CO₃
118
At 25°C, will a precipitate of Mg(OH)₂ form when a 0.0001 M solution of Mg(NO₃)₂ is adjusted to a pH of 9.0 ? At what minimum value of pH will precipitation start ? [Given : Ksp (Mg(OH)₂) = 10⁻¹¹ M³]
A
No, pH = 3.5
B
No, pH = 10.5
C
No, pH = 6.0
D
Yes, pH = 8.5
119
The solubility product of BaCrO₄ is 2.4 × 10⁻¹⁰ M². The maximum concentration of Ba(NO₃)₂ possible without precipitation in a 6 × 10⁻⁴ M K₂CrO₄ solution is :
A
4 × 10⁻⁷ M
B
1.2 × 10¹⁰ M
C
6 × 10⁻⁴ M
D
3 × 10⁻⁴ M
120
Select the correct combination –
A
The aqueous solutions of each Na₃BO₃ and Na₃PO₄ – Acidic nature
B
The aqueous solutions of each Na₃BO₃ and CH₃COONa – Basic nature
C
The aqueous solutions of each CH₃COONa and NaCN – Acidic nature
D
The aqueous solutions of each Na₃PO₄ and NH₄Cl – Acidic nature
121
According to Bronsted-Lowry concept, the relative strengths of the bases CH₃COO⁻, OH⁻ and Cl⁻ are in the order -
A
OH⁻ > CH₃COO⁻ > Cl⁻
B
Cl⁻ > OH⁻ > CH₃COO⁻
C
CH₃COO⁻ > OH⁻ > Cl⁻
D
OH⁻ > Cl⁻ > CH₃COO⁻
122
Let the solubility of AgCl in water, in 0.01 M CaCl₂, in 0.01 M NaCl and in 0.05 M AgNO₃ be s₁, s₂, s₃ and s₄ respectively. Which of the following relations between these quantities is correct –
A
s₁ > s₂ > s₃ > s₄
B
s₁ > s₂ = s₃ > s₄
C
s₄ > s₂ > s₃ > s₁
D
s₁ > s₃ > s₂ > s₄
123
For a 100 ml solution of 10⁻² M NaOH the ratio pH : pOH would be –
A
6 : 1
B
1 : 6
C
2 : 1
D
10¹⁰ : 1
124
Which of the following is the ionisation constant of 0.01 M aniline (0.02% ionised)-
A
4.0 × 10⁻⁴
B
4.0 × 10⁻⁵
C
4.0 × 10⁻⁹
D
4.0 × 10⁻¹⁰
125
The pH of a buffer solution containing 0.1 mole of acetic acid and 0.15 mole of sodium acetate is (Ka for acetic acid = 1.75 × 10⁻⁵)–
A
4.9
B
3.0
C
4.2
D
5.4
126
0.1 M acetic acid solution is titrated against 0.1 M NaOH solution. What would be the difference in pH between 1/4 and 3/4 stages of neutralisation of acid ?
A
2 log 3/4
B
2 log 1/4
C
log 1/3
D
2 log 3
127
Select the correct statement –
A
If [H⁺] = y × 10⁻ˣ then pH = x − log y
B
If [H⁺] = (1/y) × 10⁻ˣ then pH = x + log y
C
pH of a solution = 14 + log [OH⁻]
D
All of the above
128
The percentage degree of hydrolysis of a salt of weak acid (HA) and weak base (BOH) in its 0.1 M solution is found to be 10%. If the molarity of the solution is 0.05 M, the percentage hydrolysis of the salt should be -
A
5 %
B
10 %
C
20 %
D
None of these
129
If the solubility of lithium sodium hexafluoroaluminate, Li₃Na₃(AlF₆)₂ is 'a' mole/litre, the solubility product is equal to -
A
a⁸
B
12 a³
C
18 a³
D
2916 a⁸
130
The aqueous solution whose pH = 0 is-
A
Acidic
B
Alkaline
C
Amphoteric
D
Neutral
131
In the aqueous solution of MgCl₂ –
A
The number of Mg²⁺ and Cl⁻ ions are equal
B
The number of Mg²⁺ ions is half that of Cl⁻ ions
C
The number of Mg²⁺ ions is double that of Cl⁻ ions
D
None of these
132
The ionisation constant of a tribasic acid is Ka₁ & Ka₂ . If its first, second and third ionisation constants are Ka₁, Ka₂ and Ka₃ respectively then -
A
Ka = Ka₁ × Ka₂ × Ka₃
B
Ka = Ka₁/(Ka₂ × Ka₃)
C
Ka₂ = (Ka₁ × Ka)/(Ka₃)
D
None of these
133
Phenolphthalein is-
A
Acidic Indicator
B
Basic Indicator
C
Neutral
D
None of the above
134
Phenoxide ion (C₆H₅O⁻) is a weak base, with Kb = 7.7 × 10⁻⁵. Calculate the pH of a 0.20 M solution of C₆H₅O⁻ –
A
11.6
B
3.9 × 10⁻³
C
9.2
D
8.9
135
A certain buffer solution contains equal concentration of X⁻ and HX. The Kb for X⁻ is 1 × 10⁻¹⁰. The pH of the buffer is-
A
4
B
7
C
10
D
14
136
On hydrolysis of sodium carbonate, the reaction takes place between –
A
Na⁺ and water
B
Na⁺ and OH⁻
C
CO₃²⁻ and water
D
CO₃²⁻ and H⁺
137
The pOH of a basic buffer (e.g. NH₄OH/NH₄Cl) is 5. If the concentration of the salt is tripled whereas that of base remains same. What is the new value of pOH (Given log 3 ≈ 0.48) –
A
4.52
B
5.48
C
6.48
D
3.52
138
A solution contains 1 molar each of M²⁺ and X³⁺ ions. NaOH is added gradually to this solution. Which of the following statements is correct about precipitation of M(OH)₂ and X(OH)₃?
[Given: Ksp [M(OH)₂] = 4 × 10-10 ; Ksp [X(OH)₃] = 2.7 × 10-14]
A
M(OH)₂ will precipitate first as it requires 3 × 10-5 M OH- ion concentration for saturation.
B
X(OH)₃ will precipitate first as it requires 2 × 10-5 M OH- ion concentration for saturation.
C
X(OH)₃ will precipitate first as it requires 3 × 10-5 M OH- ion concentration for saturation.
D
M(OH)₂ will precipitate first as it requires 2 × 10-5 M OH- ion concentration for saturation.
139
When equal volumes of the following solutions are mixed, precipitation of CaF₂ (Ksp = 1.7 × 10⁻¹⁰) will occur only with –
A
10⁻⁴ M Ca²⁺ and 10⁻⁴ M F⁻
B
10⁻² M Ca²⁺ and 10⁻³ M F⁻
C
10⁻⁵ M Ca²⁺ and 10⁻³ M F⁻
D
10⁻³ M Ca²⁺ and 10⁻⁵ M F⁻
140
Half of the formic acid solution is neutralised on addition of a KOH solution to it. If Ka(HCOOH) = 2×10⁻⁴ then pH of the solution is – (log 2 = 0.3010)
A
3.6990
B
10.3010
C
3.85
D
4.3010
141
The correct relation between Ksp and solubility for the salt KAl(SO₄)₂ is
A
4s³
B
4s⁴
C
27s⁴
D
None
142
Nessler's reagent is ?
A
K2HgI4
B
K2HgI4 + KOH
C
K2HgI2 + KOH
D
K2HgI4 + KI
143
Solution A has pH = 3 and solution B has pH = 6. Which one of the following is correct -
A
Solution A is twice as acidic as B
B
Solution B is twice as acidic as A
C
Solution A is 1000 times more acidic than B
D
Solution B is 1000 times more acidic than A
144
The formula to calculate pKa for acetic acid is –
A
pH + ½log C
B
2pH + log C
C
pH − ½ log C
D
2 [pH + log C]
145
100 ml of 1.0 N CH₃COOH are added to 100 ml of 1.0 N NaOH solution. What will be the pH of resulting solution –
A
7.0
B
> 7.0
C
< 7.0
D
Zero
146
What is the OH⁻ concentration of an aqueous solution of a substance whose pH = 3.2 ?
A
10⁻³·⁸
B
10⁻³·²
C
10⁻¹⁰·⁸
D
10⁻¹⁰·²
147
500 ml of 0.2 M acetic acid are added to 500 ml of 0.30 M sodium acetate solution. If the dissociation constant of acetic acid is 1.5 × 10⁻⁵ then pH of the resulting solution is –
A
5.0
B
9.0
C
3.0
D
4.0
148
In a buffer solution X⁻ and HX concentration are same. If Kb value for X⁻ is 10⁻⁸ then pH of the buffer solution is –
A
8.0
B
6.0
C
4.0
D
10.0
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