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JEE • CHEMISTRY • Equilibrium

Equilibrium practice · Mixed difficulty

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Practice format and chapter quiz

These sets use single-correct-answer MCQs. They do not cover every JEE Main or JEE Advanced question format and are not full-length mock papers.

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Showing 1-30 of 680 questions
1 Easy
1 of 680
Remembering +4 | -1
The indicator used in titrating oxalic acid with caustic soda solution is:
View answer and explanation
Correct option: D
Phenolphthalein
Option D (Phenolphthalein) is correct because phenolphthalein is a suitable indicator for titrating a weak acid (oxalic acid) with a strong base (caustic soda).
2 Medium
2 of 680
Analyzing +4 | -1
K1\mathrm{K}_1 and K2\mathrm{K}_2 are equilibrium constant for reactions (i) and (ii)

N2( g)+O2( g)⇌2NO(g)…\mathrm{N}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}(\mathrm{g})\quad\ldots (i)

NO(g)⇌12 N2( g)+12O2( g)…\mathrm{NO}(\mathrm{g}) \rightleftharpoons \frac{1}{2} \mathrm{~N}_2(\mathrm{~g})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g})\quad\ldots (ii)

Then,
View answer and explanation
Correct option: A
K1=(1 K2)2\mathrm{K}_1=\left(\frac{1}{\mathrm{~K}_2}\right)^2
Option A is correct because the equilibrium constant K1 is the inverse square of K2, derived from reversing and halving the reaction.
3 Medium
3 of 680
Understanding +4 | -1
Ka1,   Ka2   and   Ka3K{a_1},\,\,\,K{a_2}\,\,\,\mathrm{and}\,\,\,K{a_3} are the respective ionisation constants for the following reactions
H2S⇋H++HS−HS−⇋H++S2−H2S⇋2H++S2−\begin{array}{l} {H_2}S\leftrightharpoons{H^ + } + H{S^ - }\\ H{S^ - }\leftrightharpoons{H^ + } + {S^{2 - }}\\ {H_2}S\leftrightharpoons2{H^ + } + {S^{2 - }} \end{array}
The correct relationship between Ka1,  Ka2 ,Ka3K{a_1},\,\,K{a_2}\,,K{a_3} is
View answer and explanation
Correct option: B
Ka3=  Ka1 ×Ka2K{a_3} = \,\,K{a_1}\, \times K{a_2}
Option B (Ka3= Ka1 ×Ka2K{a_3} = \,K{a_1}\, \times K{a_2}) is correct because the overall ionization constant is the product of the stepwise ionization constants.
4 Medium
4 of 680
Application +4 | -1
The pH\mathrm{pH} of 0.1 M−N2H40.1 \mathrm{~M}-\mathrm{N}_2 \mathrm{H}_4 solution is (For N2H4,\mathrm{N}_2 \mathrm{H}_4, Kb1=3.6×10−6,Kb2=6.4×10−12,log⁡2=0.3K_{{b}_1}=3.6 \times 10^{-6}, K_{{b}_2}=6.4 \times 10^{-12}, \log 2=0.3, log⁡3=0.48\log 3=0.48)
View answer and explanation
Correct option: C
10.78
Option C (10.78) is correct because it accurately calculates the pH of the N2H4 solution considering the first base dissociation constant.
5 Medium
5 of 680
Understanding +4 | -1
Reaction BaO2(s)⇌BaO(s)+O2(g);ΔH=−ve.{\text{Ba}}{{\text{O}}_2}(s) \rightleftharpoons {\text{BaO}}(s) + {{\text{O}}_2}(g);\Delta H = - {\text{ve}}. In equilibrium condition pressure of O2\text{O}_2 depends on:
View answer and explanation
Correct option: C
Increase temperature on equilibrium
Option C (Increase temperature on equilibrium) is correct because the reaction is exothermic, and increasing the temperature will shift the equilibrium to the left, favoring the reactants and increasing the pressure of O2.
6 Medium
6 of 680
Understanding +4 | -1
A : At equilibrium concentration of the reactant and product does not change with time for a chemical reaction.
R: The rate of reaction is zero at equilibrium.
View answer and explanation
Correct option: C
If A is correct but R is incorrect
Option C is correct because at equilibrium, the concentrations of reactants and products do not change with time, but the rate of reaction is *not* zero; the forward and reverse rates are equal.
7 Easy
7 of 680
Understanding +4 | -1
Mg2+\mathrm{M}{\mathrm{g}^{2 + }} is … than Al3+\mathrm{A}{\mathrm{l}^{3 + }}.
View answer and explanation
Correct option: C
Weak Lewis acid
Option C (Weak Lewis acid) is correct because Mg²⁺ has a smaller charge density and weaker polarizing power compared to Al³⁺, making it a weaker Lewis acid.
8 Hard
8 of 680
Application +4 | -1
For the equilibrium,

C(s)+CO2(g)⇌2CO(g);Kp=63 atm\mathrm{C}(\mathrm{s})+\mathrm{CO}_2(g) \rightleftharpoons 2 \mathrm{CO}(g) ; K_p=63 \mathrm{~atm}

at 1000 K1000 \mathrm{~K} if at equilibrium pCO=10pCO2p_{\mathrm{CO}}=10 p_{\mathrm{CO}_2} then total pressure at equilibrium is
View answer and explanation
Correct option: C
6.93 atm
Option C (6.93 atm) is correct because it is the sum of the partial pressures of CO and CO2 at equilibrium, calculated using the given Kp and the relationship between the partial pressures.
9 Hard
9 of 680
Application +4 | -1
The solids dissociate as follows: A(s) ⇋ B(g)+C(g);  KP1=x   atm2A\left( s \right)\,\leftrightharpoons\,B\left( g \right) + C\left( g \right);\,\,{K_{{P_1}}} = x\,\,\,\mathrm{at}{\mathrm{m}^2}
D(s) ⇋ C(g)+E(g);  KP2=y   atm2D\left( s \right)\,\leftrightharpoons\,C\left( g \right) + E\left( g \right);\,\,{K_{{P_2}}} = y\,\,\,\mathrm{at}{\mathrm{m}^2} The total pressure when both the solids dissociate simultaneously is
View answer and explanation
Correct option: D
2(x+y) atm2\left( {\sqrt {x + y} } \right)\mathrm{ \,atm}
Option D (2(x+y)atm2(\sqrt {x + y} )\mathrm{ atm}) is correct because it represents the total pressure derived from the equilibrium constants of the two dissociation reactions.
10 Medium
10 of 680
Understanding +4 | -1
Identify the reaction in which both products concentration and reactants concentration is appreciable
View answer and explanation
Correct option: B
X(g)+Y(g)⇌XY(g),Keq=54X(g)+Y(g) \rightleftharpoons X Y(g), {K}_{e q}=54
Option B (X(g)+Y(g)⇌XY(g),Keq=54X(g)+Y(g) \rightleftharpoons X Y(g), {K}_{e q}=54) is correct because a KeqK_{eq} value close to 1 (typically between 0.001 and 1000) indicates that both reactants and products are present in appreciable concentrations at equilibrium.
11 Easy
11 of 680
Application +4 | -1
The solubility of Sb2S3  in  water  is  1.0×10−5  mol/L\mathrm{S}{\mathrm{b}_2}{\mathrm{S}_3}\;\mathrm{in }\;\mathrm{water}\;\mathrm{ is}\;1.0 \times {10^{ - 5}}\;mol/L at 298  K298\;K. What will be its solubility product?
View answer and explanation
Correct option: A
108×10−25108 \times {10^{ - 25}}
Option D (120 kJ) is correct because it is calculated using the Gibbs free energy equation: ∆G = ∆H - T∆S.
12 Hard
12 of 680
Analyzing +4 | -1
N2( g)+3H2( g)⇌2NH3( g);K1\mathrm{N}_2(\mathrm{~g})+3 \mathrm{H}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NH}_3(\mathrm{~g}) ; \mathrm{K}_1

 N2( g)+O2( g)⇌2NO(g);K2\mathrm{~N}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}(\mathrm{g}) ; \mathrm{K}_2

H2( g)+12O2( g)⇌H2O(g);K3\mathrm{H}_2(\mathrm{~g})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g}) \rightleftharpoons \mathrm{H}_2 \mathrm{O}(\mathrm{g}) ; \mathrm{K}_3

The equilibrium constant for 2NH3( g)+52O2( g)⇌2NO(g)+3H3O(g)2 \mathrm{NH}_3(\mathrm{~g})+\frac{5}{2} \mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}(\mathrm{g})+3 \mathrm{H}_3 \mathrm{O}(\mathrm{g}) will be
View answer and explanation
Correct option: D
K2 K33 K1\frac{\mathrm{K}_2 \mathrm{~K}_3^3}{\mathrm{~K}_1}
Option D (K2 K33 K1\frac{\mathrm{K}_2 \mathrm{~K}_3^3}{\mathrm{~K}_1}) is correct because by manipulating the given equilibrium reactions, the equilibrium constant for the desired reaction can be obtained.
13 Medium
13 of 680
Analyzing +4 | -1
Solubility of Ni(OH)2\mathrm{Ni}(\mathrm{OH})_2 will be maximum in
View answer and explanation
Correct option: D
0.1M0.1 \mathrm{M} aq. solution of H2SO4\mathrm{H}_2 \mathrm{SO}_4
Option D is correct because the solubility of Ni(OH)2\mathrm{Ni}(\mathrm{OH})_2 will be maximum in 0.1M0.1 \mathrm{M} aq. solution of H2SO4\mathrm{H}_2 \mathrm{SO}_4 due to the acid-base reaction consuming hydroxide ions and shifting the equilibrium towards dissolution.
14 Medium
14 of 680
Application +4 | -1
Calculate the hydrolysis constant of the salt containing NO2−\mathrm{NO}_2^{-} ions. Ka\mathrm{K}_{\mathrm{a}} for HNO2=4.5×10−10\mathrm{HNO}_2=4.5 \times 10^{-10} and Kw=1×10−14\mathrm{K}_{\mathrm{w}}=1 \times 10^{-14}.
View answer and explanation
Correct option: A
2.2×10−52.2 \times 10^{-5}
Option A (2.2×10−52.2 \times 10^{-5}) is correct because it is the hydrolysis constant calculated using the formula Kh=KwKaK_h = \frac{{K_w}}{{K_a}}.
15 Easy
15 of 680
Analyzing +4 | -1
The degree of dissociation of CH3COOH\mathrm{C}{\mathrm{H}_3}\mathrm{COOH} is influenced by:
View answer and explanation
Correct option: D
Either of these
Option D (Either of these) is correct because the degree of dissociation of CH3COOH is influenced by the common ion effect from CH3COONa and HCl, and by acid-base reaction with NH4OH.
16 Medium
16 of 680
Application +4 | -1
At 3000 K3000 \mathrm{~K}, the equilibrium partial pressure of CO2,CO{CO}_2, {CO} and O2{O}_2 are 0.6, 0.4 and 0.2 atm respectively. Kp{K}_p for the reaction, 2CO2⇄2CO+O22 {CO}_2 \rightleftarrows 2 {CO}+{O}_2 is
View answer and explanation
Correct option: A
0.088
Option A (0.088) is correct because it is the result of correctly applying the equilibrium constant expression for the given reaction and partial pressures.
17 Easy
17 of 680
Understanding +4 | -1
Which of the following can act as a self-indicator?
View answer and explanation
Correct option: A
KMnO4KMn{O_4}
Option A (KMnO4KMn{O_4}) is correct because KMnO4KMn{O_4} acts as a self-indicator due to its intense purple color, which changes upon reduction at the endpoint of the titration.
18 Medium
18 of 680
Understanding +4 | -1
Assertion :- H2OH_2O is amphoteric in nature.

Reason :- H2OH_2O can accept a proton to form H3O+H_3O^+ ion and can donate a proton to form OH–{OH}^–
ion.
View answer and explanation
Correct option: A
If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion
Option A (If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion) is correct because water can act as both an acid and a base.
19 Medium
19 of 680
Application +4 | -1
If ΔG0\Delta {G^0} for the reaction given below is 1.7  kJ1.7\;\mathrm{ }kJ; the equilibrium constant of the reaction, 2HI(g)  ⇋  H2(g)+I2(g)2\mathrm{HI}\left( \mathrm{g} \right)\;\leftrightharpoons\;{\mathrm{H}_2}\left( \mathrm{g} \right) + {\mathrm{I}_2}\left( \mathrm{g} \right) at 25∘C25^\circ C is :
View answer and explanation
Correct option: D
0.50.5
Option D (0.50.5) is correct because it is calculated using the relationship between Gibbs free energy change and the equilibrium constant.
20 Medium
20 of 680
Understanding +4 | -1
A chemical system is in equilibrium. Addition of a catalyst would result in:
View answer and explanation
Correct option: C
A new reaction path way to reaction
Option C (A new reaction path way to reaction) is correct because a catalyst provides an alternative reaction pathway with a lower activation energy, thus speeding up the reaction without changing the equilibrium.
21 Medium
21 of 680
Understanding +4 | -1
The addition of a catalyst to the reaction system
View answer and explanation
Correct option: D
Increases the rate of forward as well as backward reaction equally
Option D (Increases the rate of forward as well as backward reaction equally) is correct because a catalyst lowers the activation energy for both forward and reverse reactions equally, thus increasing both rates.
22 Easy
22 of 680
Analyzing +4 | -1
Assertion : The equilibrium constant for the reaction

CaSO4⋅5H2O(s)=CaSO4⋅3H2O(s)+2H2O(g) is KC=[CaSO4⋅3H2O][H2O]2[CaSO4⋅5H2O]\begin{aligned} & {CaSO}_4 \cdot 5 {H}_2 {O}({s})={CaSO}_4 \cdot 3 {H}_2 {O}({s})+2 {H}_2 {O}({g}) \\ & \text { is } {K}_{{C}}=\frac{\left[{CaSO}_4 \cdot 3 {H}_2 {O}\right]\left[{H}_2 {O}\right]^2}{\left[{CaSO}_4 \cdot 5 {H}_2 {O}\right]} \end{aligned}

Reason : Equilibrium constant is the ratio of the product of molar concentration of the substances produced to the product of the molar concentrations of reactants with each concentrations term raised to the power equal to the respective stoichiometric constant.
View answer and explanation
Correct option: D
If assertion is false but reason is true
Option D is correct because the equilibrium constant for a heterogeneous reaction only includes gaseous or aqueous species, and the concentration of solids is considered unity.
23 Medium
23 of 680
Application +4 | -1
A buffer solution is prepared in which the concentration of NH3\mathrm{N}{\mathrm{H}_3} is 0.30  M0.30\;M and the concentration of NH4+\mathrm{NH}_4^ + is 0.20  M0.20\;M. If the equilibrium constant, Kb{K_b} for NH3\mathrm{N}{\mathrm{H}_3} equals 1.8×10−51.8 \times {10^{ - 5}} what is the pH of this solution?
(log⁡2.7=0.43)(\log 2.7 = 0.43)
View answer and explanation
Correct option: C
9.439.43
Option C (9.439.43) is correct because it is calculated using the Henderson-Hasselbalch equation for a basic buffer solution.
24 Medium
24 of 680
Application +4 | -1
If equilibrium constant is 2.6×1082.6 \times 10^8 then find the value of ΔG∘\Delta {G}^{\circ}.
View answer and explanation
Correct option: A
−43.36 kJ-43.36 \mathrm{~kJ}
Option A (−43.36 kJ-43.36 \mathrm{~kJ}) is correct because it is calculated using the Gibbs free energy equation with the given equilibrium constant.
25 Medium
25 of 680
Analyzing +4 | -1
Which of the following when mixed, will give a solution with
pH greater than 7?
View answer and explanation
Correct option: B
100 mL100 \mathrm{~mL} of 0.1 M CH3COOH+100 mL0.1 \mathrm{~M} \mathrm{~CH}_3 \mathrm{COOH}+100 \mathrm{~mL} of 0.1 M KOH0.1 \mathrm{~M} \mathrm{~KOH}
The correct answer is B (100 mL100 \mathrm{~mL} of 0.1 M CH3COOH+100 mL0.1 \mathrm{~M} \mathrm{~CH}_3 \mathrm{COOH}+100 \mathrm{~mL} of 0.1 M KOH0.1 \mathrm{~M} \mathrm{~KOH}) because it forms a basic buffer solution after the reaction.
26 Medium
26 of 680
Analyzing +4 | -1
A vessel contains A(g)\mathrm{A}(\mathrm{g}) and B(g)\mathrm{B}(\mathrm{g}) at 2 atm2 \mathrm{~atm} and 4 atm4 \mathrm{~atm} respectively at TK\mathrm{TK}, the mixture is allowed to attain equilibrium at TK\mathrm{TK}, according to the reaction

8B(g)⇌8A(g)+C(s)8 \mathrm{B}(\mathrm{g}) \rightleftharpoons 8 \mathrm{A}(\mathrm{g})+\mathrm{C}(\mathrm{s})

At equilibrium, (nAnB)eq =(nBnA)initial \left(\frac{\mathrm{n_A}}{\mathrm{n_B}}\right)_{\text {eq }}=\left(\frac{\mathrm{n_B}}{\mathrm{n_A}}\right)_{\text {initial }}
Find the value of y\mathrm{y} if Kc=2y\mathrm{K_c}=2^\mathrm{y}
View answer and explanation
Correct option: A
8
Option A (8) is correct because the equilibrium constant Kc is calculated to be 28, thus y=8.
27 Medium
27 of 680
Application +4 | -1
In which of the following cases, pH is greater than 7?
View answer and explanation
Correct option: C
50 mL of 0.1 M CH3COOHC{H_3}COOH + 50 mL of 0.1 M KOH
Option C (50 mL of 0.1 M CH3COOHC{H_3}COOH + 50 mL of 0.1 M KOH) is correct because it involves the reaction of a weak acid (CH3COOHCH_3COOH) with a strong base (KOH), resulting in a salt of a weak acid and strong base, which hydrolyzes to give a pH greater than 7.
28 Medium
28 of 680
Analyzing +4 | -1
A: HCl,HNO3{HCl}, {HNO}_3 and H2SO4{H}_2 {SO}_4 are equally strong acids in water.
R: Water is a stronger acid than alcohols.
View answer and explanation
Correct option: B
If both A and R are correct, but R is not the correct explanation of A
Option B is correct because both the assertion and the reason are correct statements, but the reason does not explain the assertion. The leveling effect explains the assertion.
29 Medium
29 of 680
Analyzing +4 | -1
The degree of hydrolysis of which of the
following salt is independent of the
concentration of salt solution?
View answer and explanation
Correct option: D
NaCl{NaCl}
The correct answer is D (NaCl{NaCl}) because it is a salt of a strong acid and a strong base, and therefore does not undergo hydrolysis. Its degree of hydrolysis is zero and independent of concentration.
30 Easy
30 of 680
Analyzing +4 | -1
Pure ammonia is placed in a vessel at temperature where its dissociation constant (α\mathrm{\alpha }) is appreciable. At equilibrium,
View answer and explanation
Correct option: D
Concentration of H2{\mathrm{H}_2} is less than that of N2{\mathrm{N}_2}
Option D is correct because at equilibrium, the concentration of H2 will be less than N2 due to the stoichiometry of the ammonia dissociation reaction.
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