JEE Advanced (Single Correct Type): Equilibrium | Chapter-wise Tests for JEE Main & Advanced PDF Download

Q.1. According to Lewis concept, an acid is:
(a) proton donor
(b) electron pair donor
(c) electron pair acceptor
(d) proton acceptor

Correct Answer is option (c)
According to Lewis concept, an acid is electron pair acceptor

Q.2. Ostwald’s dilution law is applicable to:
(a) Strong electrolytes only
(b) Weak electrolyte only
(c) Non-electrolytes
(d) Strong and weak electrolytes

Correct Answer is option (b)
Ostwald’s dilution law is applicable to weak electrolyte only

Q.3. The pH of a solution of hydrochloric acid is 4. The molarity of the solution is:
(a) 4.0
(b) 0.4
(c) 0.0001
(d) 0.04

Correct Answer is option (c)

pH = – log [H⁺] , Here [H⁺] = 10-4 , Molarity = 0.0001 M

Q.4. The strong conjugate base is
(a) NO₃^2-
(b) Cl^–
(c) SO₄^2-
(d) CH₃COO^–

Correct Answer is option (d)

CH₃COO^– is the strongest conjugate base because CH₃COOH is a weak acid.

Q.5. Which of the following pairs constitutes a buffer ?
(a) NaOH and HCl
(b) HNO₃ and NH₄NO₃
(c) HCl and KCl
(d) HNO₂ and NaNO₂

Correct Answer is option (d)
HNO₂ and NaNO₂ represent a buffer mixture.

Q.6. Le Chatelier’s principle is applicable to:
(a) only homogeneous chemical reversible reactions
(b) only heterogeneous chemical reversible reactions
(c) only physical equilibria
(d) all systems, chemical or physical in equilibrium.

Correct Answer is option (d)
Le Chatelier’s principle is applicable to all systems, chemical or physical in equilibrium.

Q.7. Which of the following is the weakest base?
(a) NaOH
(b) Ca(OH)₂
(c) NH₄OH
(d) KOH

Correct Answer is option (c)
NH⁴OH is the weakest base.

Q.8. When NH₄Cl is added to NH₄OH solution the dissociation of ammonium hydroxide is reduced. It is due to:
(a) common ion effect
(b) hydrolysis
(c) oxidation
(d) reduction

Correct Answer is option (a)
ammonium hydroxide is reduced due to presence of common ion NH₄⁺

Q.9. For the reversible reaction
N₂ (g) + 3H₂(g) ⇋ 2NH₃ + Heat
The equilibrium shifts in forward direction
(a) by increasing the concentration of NH₃(g)
(b) by decreasing the pressure
(c) by decreasing the concentration of N₂ and H₂
(d) by increasing pressure and decreasing temperature

Correct Answer is option (d)
Le Chatelier’s principle suggests that in the formation of ammonia, the equilibrium shifts in forward direction by increasing pressure and decreasing temperature.

Q.10. A base according to Bronsted concept is a substance which can:
(a) lose pair of electron
(b) donate protons
(c) gain a pair of electrons
(d) accept protons

Correct Answer is option (d)
A base according to Bronsted concept is a substance which can accept protons.

Q.11. 15 moles of H₂ and 5.2 moles of I2 are mixed and allowed to attain equilibrium at 500°C. At equilibrium, the concentration of HI is found to be 10 moles. The equilibrium constant for the formation of HI is:
(a) 50
(b) 15
(c) 100
(d) 25

Correct Answer is option (a)

Q.12. At temperature T, a compound AB2(g) dissociates according to the reaction
2AB2(g) ⇌ 2AB(g) + B2(g)
With degree of dissociation a, which is small compared with unity. The expression of Kp, in terms of α and total pressure P_T is
(a)
(b)
(c)
(d)  

Correct Answer is option (a)

Q.13. 40% of a mixture of 0.2 mole of N₂ and 0.6 mole of H₂ react to give NH₃ according to the equation N₂(g) + 3H₂(g) ⇌ 2NH₃(g) at given temperature and pressure. Then the ratio of the final volume to the initial volumes of gases are as
(a) 4:5
(b) 5:4
(c) 7:10
(d) 8:5

Correct Answer is option (a)

Total number of moles at equilibrium

= 0.2 – x + 0.6 – 3x + 2x

= 0.8 – 2x = 0.8 – 2 x 0.08= 0.8 – 0.16 = 0.64

Q.14. pH of a 0.1 M monobasic acid solution is found to be 2. Its osmotic pressure of this solution at a temperature of ‘T(K)’ is
(a) 0.1 RT
(b) 0.11 RT
(c) 1.1 RT
(d) 0.01 RT

Correct Answer is option (b)

Q.15. What is the approximate OH^- ion concentration of a 0.150 M NH₃ solution? (Kb = 1.75x 10^–5)
(a) 2.62 x 10^–6
(b) 4.6 x 10^–6
(c) 1.62 x 10^–3
(d) 3.6 x 10^–3

Correct Answer is option (c)

Q.16. Carbonic acid, H2CO3, is a diprotic acid for which K₁ = 10^–7 and K₂ = 10–11. Which solution will produce a pH closest to 9?
(a) 0.1 M H₂CO₃
(b) 0.1 M Na₂CO₃
(c) 0.1 M NaHCO₃
(d) 0.1 M NaHCO₃ and 0.1 M Na₂CO₃

Correct Answer is option (c)

Q.17. When pure water is saturated with CaCO₃ and CaC₂O₄, the concentration of calcium ion in the solution under equilibrium is 8.426 × 10^–5 M. If the ratio of the solubility product of CaCO₃ to that of CaC₂O₄ is 2.087, what is the solubility product of CaCO₃ in pure water?

(a) 4.80 × 10^–8
(b) 9.60 × 10^–9
(c) 9.60 × 10^–8
(d) 4.80 × 10^–9

Correct Answer is option (d)

Q.18. The self-ionisation constant of NH₃ at 50°C is given by
How many NH₂^- ions are present per cm3 of pure liquid NH₃? (Assume Avogadro’s number = 6 x 10²³)
(a) 6 x 10⁶ 
(b) 6x 10⁵
(c) 6 x 10^-5 
(d) 6 x 10^-6

Correct Answer is option (b)

NH₂^- ions per cm³ of liquid NH₃ 

Q.19. A buffer solution is prepared by mixing 10 ml of 1.0 M acetic acid and 20 ml of 0.5 M sodium acetate and then diluted to 100 ml with distilled water. If the pKa of CH₃COOH is 4.76, what is the pH of the buffer solution prepared?
(a) 5.21
(b) 4.76
(c) 4.34
(d) 5.21

Correct Answer is option (b)

Q.20. The pKb value of ammonium hydroxide is 4.75. An aqueous solution of ammonium hydroxide is titrated with HCl. The pH of the solution at the point where half of ammonium hydroxide has been neutralised will be
(a) 9.25
(b) 8.25
(c) 7.50
(d) 4.75

Correct Answer is option (a)