Equilibrium NEET Previous Year Questions (PYQs)
Practice NEET previous year questions from Equilibrium. These MCQs cover chemical equilibrium, ionic equilibrium, acids-bases, buffers, solubility product, Kc–Kp relations and Le Chatelier’s principle with answers and clear explanations.
👉 Read theory:
Equilibrium Chapter Notes
Q1. Which condition favours maximum formation of product in an exothermic reaction?
(NEET 2018)
- (A) High temperature, low pressure
- (B) High temperature, high pressure
- (C) Low temperature, low pressure
- (D) Low temperature, high pressure
Show Answer
(D)
Show Explanation
Exothermic reactions are favoured at low temperature. High pressure favours side with fewer moles of gas.
Q2. The solubility of BaSO4 in water is 2.42 × 10−3 g L−1. The value of Ksp is:
(NEET 2018)
- (A) 1.08 × 10−10
- (B) 1.08 × 10−12
- (C) 1.08 × 10−8
- (D) 1.08 × 10−14
Show Answer
(A)
Show Explanation
Solubility is converted to molar solubility and Ksp = s2.
Q3. Which salt gives highest pH in aqueous solution?
(NEET 2014)
- (A) KCl
- (B) NaCl
- (C) Na2CO3
- (D) CuSO4
Show Answer
(C)
Show Explanation
Na2CO3 is a salt of strong base and weak acid, hence basic.
Q4. If equilibrium constant K is very large, the reaction mixture contains:
(NEET 2015)
- (A) Mostly reactants
- (B) Mostly products
- (C) Equal amounts
- (D) No reactants
Show Answer
(B)
Show Explanation
Large K value indicates reaction proceeds almost to completion.
Q5. Which expression is correct at equilibrium?
(NEET 2015)
- (A) ΔG = 0
- (B) ΔG > 0
- (C) ΔH = 0
- (D) ΔS = 0
Show Answer
(A)
Show Explanation
At equilibrium, Gibbs free energy change is zero.
Q6. Which solution acts as a basic buffer?
(NEET 2019)
- (A) NH4Cl + NH4OH
- (B) NaCl + HCl
- (C) CH3COOH + NaCl
- (D) HCl + NaOH
Show Answer
(A)
Show Explanation
Basic buffer = weak base + salt of weak base.
Q7. Which compound acts as Lewis acid?
(NEET 2013)
- (A) NH3
- (B) H2O
- (C) BF3
- (D) OH−
Show Answer
(C)
Show Explanation
BF3 is electron deficient and can accept electron pairs.
Q8. Which of the following has minimum solubility?
(NEET 1995)
- (A) AgCl
- (B) AgBr
- (C) AgI
- (D) AgF
Show Answer
(C)
Show Explanation
Lower Ksp implies lower solubility. AgI has lowest Ksp.
Q9. For the reaction N2 + 3H2 ⇌ 2NH3, increasing pressure will:
(NEET 2014)
- (A) Shift equilibrium left
- (B) Shift equilibrium right
- (C) No effect
- (D) Stop reaction
Show Answer
(B)
Show Explanation
Fewer moles of gas on product side, so high pressure favours forward reaction.
Q10. pH of 0.01 M NaOH solution is:
(NEET 2019 Odisha)
- (A) 2
- (B) 9
- (C) 12
- (D) 7
Show Answer
(C)
Show Explanation
pOH = 2 ⇒ pH = 14 − 2 = 12.
Q11. Which ion is conjugate base of HF?
(NEET 2019)
- (A) H2F+
- (B) OH−
- (C) F−
- (D) H3O+
Show Answer
(C)
Show Explanation
HF donates H+, leaving F− as conjugate base.
Q12. Which solution is basic in nature?
(NEET 2020)
- (A) NH4Cl
- (B) NH4NO3
- (C) NaCl
- (D) CH3COONa
Show Answer
(D)
Show Explanation
Sodium acetate is salt of weak acid and strong base.
Q13. The value of pH of blood remains nearly constant due to:
(NEET 1995)
- (A) Enzymes
- (B) Hormones
- (C) Buffer action
- (D) Oxygen
Show Answer
(C)
Show Explanation
Blood contains buffer systems that resist pH change.
Q14. Kp and Kc are related as:
(NEET 2011)
- (A) Kp = Kc
- (B) Kp = Kc(RT)Δn
- (C) Kp = Kc/RT
- (D) Kp = RT/Kc
Show Answer
(B)
Show Explanation
Δn = moles of gaseous products − reactants.
Q15. Which will increase solubility of AgCl?
(NEET 2016)
- (A) NaCl
- (B) HCl
- (C) NH3
- (D) AgNO3
Show Answer
(C)
Show Explanation
NH3 forms complex with Ag+, increasing solubility.
Q16. Ionic product of water increases with:
(NEET 1998)
- (A) Increase in pressure
- (B) Decrease in temperature
- (C) Increase in temperature
- (D) Addition of salt
Show Answer
(C)
Show Explanation
Auto-ionisation of water increases with temperature.
Q17. For weak acid HA, stronger conjugate base corresponds to:
(NEET 1999)
- (A) Strong acid
- (B) Weak acid
- (C) Neutral acid
- (D) Strong base
Show Answer
(B)
Show Explanation
Weaker the acid, stronger is its conjugate base.
Q18. Which equilibrium shift occurs on increasing temperature for endothermic reaction?
(NEET 2014)
- (A) Backward
- (B) Forward
- (C) No change
- (D) Stops
Show Answer
(B)
Show Explanation
Heat acts as reactant in endothermic reactions.
Q19. pH of pure water at 25°C is:
(NEET 1994)
- (A) 5
- (B) 6
- (C) 7
- (D) 8
Show Answer
(C)
Show Explanation
At 25°C, [H+] = 10−7 M.
Q20. Buffer solutions resist pH change because:
(NEET 2012)
- (A) They contain strong acids
- (B) They contain strong bases
- (C) They neutralise added acid or base
- (D) They dilute solution
Show Answer
(C)
Show Explanation
Buffers neutralise small amounts of added acid or base.
👉 More Equilibrium NEET PYQs will be added gradually.