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JEE • CHEMISTRY • Equilibrium

Equilibrium practice · Easy

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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 161 questions
1 Easy
1 of 161
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 Easy
2 of 161
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.
3 Easy
3 of 161
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.
4 Easy
4 of 161
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.
5 Easy
5 of 161
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.
6 Easy
6 of 161
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.
7 Easy
7 of 161
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.
8 Easy
8 of 161
Remembering +4 | -1
2SO2(g)+O2(g)→ Catalyst 2SO3(g)2 \mathrm{SO_2(g})+\mathrm{O}_2(\mathrm{g}) \xrightarrow{\text { Catalyst }} 2 \mathrm{SO}_3(\mathrm{g})
Identify the catalyst from the options given below:
View answer and explanation
Correct option: A
V2O5\mathrm{V}_2 \mathrm{O}_5
Option A (V2O5\mathrm{V}_2 \mathrm{O}_5) is correct because Vanadium pentoxide (V2O5\mathrm{V}_2 \mathrm{O}_5) is the catalyst used in the Contact process for the production of SO3\mathrm{SO}_3.
9 Easy
9 of 161
Understanding +4 | -1
The KC{K_C} for H2(g)+I2(g)2HI(g){H_2}(g) + {I_2}(g)2HI(g) is 64, if the volume of the container is reduced to one-half of its
original volume, the value of equilibrium constant will be
View answer and explanation
Correct option: B
64
Option B (64) is correct because the equilibrium constant, Kc, is independent of volume changes for the given reaction.
10 Easy
10 of 161
Understanding +4 | -1
NH4Cl\mathrm{N}{\mathrm{H}_4}\mathrm{Cl} is acidic because
View answer and explanation
Correct option: A
On hydrolysis NH4Cl\mathrm{N}{\mathrm{H}_4}\mathrm{Cl} gives weak base NH4OH\mathrm{N}{\mathrm{H}_4}\mathrm{OH} and strong acid HCl
Option A is correct because ammonium chloride (NH4ClNH_4Cl) is a salt of a weak base (NH4OHNH_4OH) and a strong acid (HCl), making it acidic due to the hydrolysis of the ammonium ion.
11 Easy
11 of 161
Remembering +4 | -1
Phenolphthalein is a:
View answer and explanation
Correct option: A
Weak acid
Option A (Weak acid) is correct because phenolphthalein is a weak organic acid that exists in equilibrium between its protonated and deprotonated forms.
12 Easy
12 of 161
Application +4 | -1
For a system, A+2B⇌CA+2 B \rightleftharpoons C, the equilibrium concentration are [A]=0.06[A]=0.06, [B]=0.12[B]=0.12, and [C]=0.216[C]=0.216. The KcK_c for the reaction is
View answer and explanation
Correct option: D
250
Option D (250) is correct because it is calculated by substituting the equilibrium concentrations into the Kc expression.
13 Easy
13 of 161
Remembering +4 | -1
Amines behave as
View answer and explanation
Correct option: B
Lewis base
Option B (Lewis base) is correct because amines have a lone pair of electrons on the nitrogen atom, making them electron-pair donors, which is the definition of a Lewis base.
14 Easy
14 of 161
Understanding +4 | -1
The salt that does not hydrolyse, is:
View answer and explanation
Correct option: D
CaCl2\mathrm{CaC}{\mathrm{l}_2}
Option D (CaCl2\mathrm{CaC}{\mathrm{l}_2}) is correct because it is a salt formed from a strong acid (HCl) and a strong base (Ca(OH)₂), and therefore does not hydrolyze.
15 Easy
15 of 161
Understanding +4 | -1
The conjugate base of H2PO4−{\mathrm{H}_2}\mathrm{PO}_4^ - is:
View answer and explanation
Correct option: A
HPO42−\mathrm{HPO}_4^{2 - }
The correct answer is A (HPO42−\mathrm{HPO}_4^{2 - }) because the conjugate base is formed by removing a proton (H+) from the acid.
16 Easy
16 of 161
Understanding +4 | -1
If ss and SS are respectively solubility and solubility product of a sparingly soluble binary electrolyte then :
View answer and explanation
Correct option: C
s=S1/2{s}={S}^{1 / 2}
Option C (s=S1/2{s}={S}^{1 / 2}) is correct because for a binary electrolyte, the solubility is the square root of the solubility product.
17 Easy
17 of 161
Analyzing +4 | -1
Assertion : For the reaction,

2NH3( g)⇌N2( g)+3H2( g)2 {NH}_3({~g}) \rightleftharpoons {N}_2({~g})+3 {H}_2({~g}), the unit of KpK_p will be atm.

Reason : Unit of KpK_p is (atm)Δn(a t m)^{\Delta n}.
View answer and explanation
Correct option: D
If assertion is false but reason is true
Option D is correct. The assertion is false because the unit of Kp is atm2, not atm, while the reason is true as the unit of Kp is (atm)^∆n.
18 Easy
18 of 161
Understanding +4 | -1
Consider a saturated solution. (i.e., a solution in equilibrium with solid solute) of sodium chloride. If the temperature is raised, then for
NaCl(s)+aq ⇌ NaCl(aq);ΔH=+veNaCl(s) + aq\, \rightleftharpoons \,NaCl(aq);\Delta H = + ve
View answer and explanation
Correct option: A
More solid will dissolve
Option A (More solid will dissolve) is correct because the dissolution of NaCl is endothermic, so increasing the temperature will shift the equilibrium towards dissolution according to Le Chatelier's principle.
19 Easy
19 of 161
Application +4 | -1
Degree of dissociation of0.1  N0.1\;\mathrm{ }N CH3COOH\mathrm{C}{\mathrm{H}_3}\mathrm{COOH} is (dissociation constant =1×10−5= 1 \times {10^{ - 5}})
View answer and explanation
Correct option: D
10−2{10^{ - 2}}
Option D (10−2{10^{ - 2}}) is correct because the degree of dissociation is calculated using the formula α=KaC\alpha = \sqrt{\frac{K_a}{C}}.
20 Easy
20 of 161
Remembering +4 | -1
In the titration of Na2CO3  and  HCl\mathrm{N}{\mathrm{a}_2}\mathrm{C}{\mathrm{O}_3}\;\mathrm{and}\;\mathrm{ HCl}, the indicator used is
View answer and explanation
Correct option: A
Methyl orange
Option A (Methyl orange) is correct because it is the appropriate indicator for titrations where the equivalence point is on the acidic side, such as with Na2CO3 and HCl.
21 Easy
21 of 161
Understanding +4 | -1
In which of the following equilibrium, change in volume of the system does not alter the number of moles?
View answer and explanation
Correct option: A
N2(g)+O2(g)  ⇋  2NO(g){\mathrm{N}_2}\left( \mathrm{g} \right) + {\mathrm{O}_2}\left( \mathrm{g} \right)\;\leftrightharpoons\;2\mathrm{NO}\left( \mathrm{g} \right)
Option A (N2(g)+O2(g);⇋;2NO(g){\mathrm{N}_2}\left( \mathrm{g} \right) + {\mathrm{O}_2}\left( \mathrm{g} \right)\\;\leftrightharpoons\\;2\mathrm{NO}\left( \mathrm{g} \right)) is correct because the number of moles of gaseous reactants equals the number of moles of gaseous products, so a change in volume will not shift the equilibrium.
22 Easy
22 of 161
Application +4 | -1
A weak acid HXHX has dissociation constant 10−5{10^{ - 5}}. The pHpH of 0.1  M0.1\;M solution of this acid will be
View answer and explanation
Correct option: B
3
Option B (3) is correct because the pH of a weak acid solution is calculated using the formula pH = -log[H+], where [H+] = √(Ka * C).
23 Easy
23 of 161
Application +4 | -1
Which solution has pH equal to 10?
View answer and explanation
Correct option: A
10−4  M  KOH{10^{ - 4}}\;\mathrm{M}\;\mathrm{ KOH}
Option A (10−4  M  KOH{10^{ - 4}}\;\mathrm{M}\;\mathrm{ KOH}) is correct because a KOH concentration of 10-4 M corresponds to a pOH of 4, and thus a pH of 10.
24 Easy
24 of 161
Remembering +4 | -1
When the pH\mathrm{pH} of a solution is 2, the hydrogen ion concentration is:
View answer and explanation
Correct option: B
1×10−2  M1 \times {10^{ - 2}}\;M
Option B (1×10−2  M1 \times {10^{ - 2}}\;M) is correct because pH is defined as the negative logarithm of hydrogen ion concentration, so if pH is 2, the hydrogen ion concentration is 10−210^{-2} M.
25 Easy
25 of 161
Application +4 | -1
A volume of 10 ml10 \mathrm{~ml} of a strong acid solution of pH=2.0\mathrm{pH}=2.0 are mixed with 990 ml990 \mathrm{~ml} of a buffer solution of pH=4.0.\mathrm{pH}=4.0. The pH\mathrm{pH} of the resulting solution will be (approximately)
View answer and explanation
Correct option: D
3.5
Option D (3.5) is correct because adding a strong acid to a buffer will decrease the pH, but the buffer resists large changes, resulting in a pH slightly lower than 4.
26 Easy
26 of 161
Understanding +4 | -1
Which aqueous solution will have pH less than 7?
View answer and explanation
Correct option: D
Fe3+\mathrm{F}{\mathrm{e}^{3 + }}
Option D (Fe3+\mathrm{F}{\mathrm{e}^{3 + }}) is correct because Fe3+\mathrm{F}{\mathrm{e}^{3 + }} ions undergo hydrolysis to produce H+H^+ ions, making the solution acidic (pH < 7).
27 Easy
27 of 161
Remembering +4 | -1
The indicators used in the titration of iodine against sodium thiosulphate is
View answer and explanation
Correct option: A
Starch
Option A (Starch) is correct because starch acts as an indicator in iodometric titrations, forming a blue complex with iodine, which disappears at the endpoint.
28 Easy
28 of 161
Remembering +4 | -1
Methyl orange is an indicator in acid-alkali titration. It gives:
View answer and explanation
Correct option: D
Yellow colour in alkaline medium and red colour in acid medium
Option D (Yellow colour in alkaline medium and red colour in acid medium) is correct because methyl orange exhibits these color changes in different pH environments.
29 Easy
29 of 161
Understanding +4 | -1
Which statement is correct?
View answer and explanation
Correct option: C
CH3COOH\mathrm{C}{\mathrm{H}_3}\mathrm{COOH} is a weak acid
Option C (CH3COOH\mathrm{C}{\mathrm{H}_3}\mathrm{COOH} is a weak acid) is correct because acetic acid is a weak acid that only partially dissociates in water.
30 Easy
30 of 161
Understanding +4 | -1
In an equilibrium reaction for which ΔG∘=0\Delta G^{\circ}=0, the equilibrium constant K\mathrm{K} should be equal to:
View answer and explanation
Correct option: B
1
Option B (1) is correct because when ΔG∘=0\Delta G^{\circ} = 0, the equilibrium constant K is equal to 1, as derived from the equation ΔG∘=−RTln⁡K\Delta G^{\circ} = -RT \ln K.
Revision notes and key takeaways

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Key Takeaways

  • ✓ This set contains 161 single-correct-answer MCQs on Equilibrium.
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  • ✓ Sign in to save submitted answers. Revisit incorrect answers alongside your textbook or class notes.
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