NEET Equilibrium PYQ practice sheet

14 previous-year NEET Chemistry questions from Equilibrium, newest papers first. Equilibrium carries 19 of the Chemistry questions in NEET 2020 to 2026, so this is a good place to test yourself after revising the chapter. Marking: +4 correct, −1 wrong.

1. 1.

   RE-NEET 2026

   The correct order of solubility of the given salts in water at $298$ K is Salt and $K_{sp}$ at $298$ K: AgBr: $5.0\times10^{-13}$ $\mathrm{Zn(OH)_2}$: $1.0\times10^{-15}$ $\mathrm{Hg_2Cl_2}$: $1.3\times10^{-18}$

   • (A)
     $\mathrm{Zn(OH)_2} > \mathrm{AgBr} > \mathrm{Hg_2Cl_2}$
   • (B)
     $\mathrm{Hg_2Cl_2} > \mathrm{AgBr} > \mathrm{Zn(OH)_2}$
   • (C)
     $\mathrm{AgBr} > \mathrm{Zn(OH)_2} > \mathrm{Hg_2Cl_2}$
   • (D)
     $\mathrm{Hg_2Cl_2} > \mathrm{Zn(OH)_2} > \mathrm{AgBr}$
2. 2.

   NEET 2026

   In a qualitative analysis, $\mathrm{Bi^{3+}}$ is detected by appearance of precipitate of $\mathrm{BiO(OH)(s)}$. Calculate pH when the following equilibrium exists at 298 K. $\mathrm{BiO(OH)(s)\rightleftharpoons BiO^{+}(aq)+OH^{-}(aq)}$, $K=4\times10^{-10}$ (Given: $\log2=0.3010$)

   • (A)
     4.699
   • (B)
     9.301
   • (C)
     5.286
   • (D)
     8.714
3. 3.

   NEET 2026

   At 298 K, a certain buffer solution contains equal concentrations of $\mathrm{X^-}$ and HX, $K_b$ for $\mathrm{X^-}$ is $10^{-10}$. What is the pH of this buffer solution?

   • (A)
     6
   • (B)
     4
   • (C)
     10
   • (D)
     2
4. 4.

   NEET 2026

   Phenolphthalein is used as an indicator for the titration of sodium hydroxide solution against a standard solution of oxalic acid. The colour change that is observed at an alkaline pH close to the equivalence point during this titration is:

   • (A)
     pink to colourless
   • (B)
     yellow to pinkish red
   • (C)
     colourless to pink
   • (D)
     pinkish red to yellow
5. 5.

   NEET 2026

   Given below are certain reactions. Identify the reaction for which $K_P\neq K_C$.

   • (A)
     $\mathrm{N_2(g)+3H_2(g)\rightleftharpoons2NH_3(g)}$
   • (B)
     $\mathrm{H_2(g)+I_2(g)\rightleftharpoons2HI(g)}$
   • (C)
     $\mathrm{H_2O(g)+CO(g)\rightleftharpoons H_2(g)+CO_2(g)}$
   • (D)
     $\mathrm{N_2(g)+O_2(g)\rightleftharpoons2NO(g)}$
6. 6.

   NEET 2024

   For the reaction $\mathrm{2A\rightleftharpoons B+C}$, $K_c=4\times10^{-3}$. At a given time, the composition of reaction mixture is: $[A]=[B]=[C]=2\times10^{-3}$ M. Then, which of the following is correct?

   • (A)
     Reaction is at equilibrium.
   • (B)
     Reaction has a tendency to go in forward direction.
   • (C)
     Reaction has gone to completion in forward direction.
   • (D)
     Reaction has a tendency to go in backward direction.
7. 7.

   NEET 2024

   In which of the following equilibria, $K_p$ and $K_c$ are NOT equal?

   • (A)
     $\mathrm{PCl_5(g)\rightleftharpoons PCl_3(g)+Cl_2(g)}$
   • (B)
     $\mathrm{H_2(g)+I_2(g)\rightleftharpoons2HI(g)}$
   • (C)
     $\mathrm{CO(g)+H_2O(g)\rightleftharpoons CO_2(g)+H_2(g)}$
   • (D)
     $\mathrm{2BrCl(g)\rightleftharpoons Br_2(g)+Cl_2(g)}$
8. 8.

   NEET 2024

   Consider the following reaction in a sealed vessel at equilibrium with concentrations of $\mathrm{N_2}=3.0\times10^{-3}$ M, $\mathrm{O_2}=4.2\times10^{-3}$ M and $\mathrm{NO}=2.8\times10^{-3}$ M. $\mathrm{2NO(g)\rightleftharpoons N_2(g)+O_2(g)}$ If 0.1 mol $\mathrm{L^{-1}}$ of NO(g) is taken in a closed vessel, what will be degree of dissociation ($\alpha$) of NO(g) at equilibrium?

   • (A)
     0.717
   • (B)
     0.00889
   • (C)
     0.8889
   • (D)
     0.0889
9. 9.

   NEET 2023

   Amongst the given options which of the following molecules / ion acts as a Lewis acid?

   • (A)
     $\mathrm{OH^-}$
   • (B)
     $\mathrm{NH_3}$
   • (C)
     $\mathrm{H_2O}$
   • (D)
     $\mathrm{BF_3}$
10. 10.

    NEET 2022

    The pH of the solution containing 50 mL each of 0.10 M sodium acetate and 0.01 M acetic acid is: [Given $pK_a$ of $\mathrm{CH_3COOH}=4.57$]

    • (A)
      2.57
    • (B)
      5.57
    • (C)
      3.57
    • (D)
      4.57
11. 11.

    NEET 2022

    $$3\mathrm{O_2(g)}\rightleftharpoons2\mathrm{O_3(g)}$$

    for the above reaction at 298 K, $K_c$ is found to be $3.0\times10^{-59}$. If the concentration of $\mathrm{O_2}$ at equilibrium is 0.040 M, then the concentration of $\mathrm{O_3}$ in M is:

    • (A)
      $1.2\times10^{21}$
    • (B)
      $4.38\times10^{-32}$
    • (C)
      $1.9\times10^{-63}$
    • (D)
      $2.4\times10^{31}$
12. 12.

    NEET 2021

    The $\mathrm{p}K_b$ of dimethylamine and $\mathrm{p}K_a$ 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)
      7.75
    • (C)
      8.50
    • (D)
      5.50
13. 13.

    NEET 2020

    HCl was passed through a solution of $\mathrm{CaCl_2}$, $\mathrm{MgCl_2}$ and $\mathrm{NaCl}$. Which of the following compound(s) crystallise(s)?

    • (A)
      Both $\mathrm{MgCl_2}$ and $\mathrm{CaCl_2}$
    • (B)
      Only NaCl
    • (C)
      Only $\mathrm{MgCl_2}$
    • (D)
      NaCl, $\mathrm{MgCl_2}$ and $\mathrm{CaCl_2}$
14. 14.

    NEET 2020

    Find out the solubility of $\mathrm{Ni(OH)_2}$ in $0.1$ M NaOH. Given that the ionic product of $\mathrm{Ni(OH)_2}$ is $2\times10^{-15}$.

    • (A)
      $2\times10^{-13}$ M
    • (B)
      $2\times10^{-8}$ M
    • (C)
      $1\times10^{-13}$ M
    • (D)
      $1\times10^{8}$ M