Chemical & Ionic Equilibrium · JEE Main previous year questions

277 questions asked across 20 exam years, newest first

Year-wise papers Topic-wise questions

Practise this topic

2026 40 questions

Q732026 · 24 Jan 2026 · Shift 1· Numerical answer
Consider two Group IV metal ions $X^{2 +}$ and $Y^{2 +}$ . A solution containing $0.01 M X^{2 +}$ and $0.01 M Y^{2 +}$ is saturated with $H_{2} S$ . The pH at which the metal sulphide YS will form as a precipitate is ____ . (Nearest integer) (Given: $K_{sp} (XS) = 1 \times 1 0^{- 22}$ at $2 5^{\circ} C$ , $K_{sp} (YS) = 4 \times 1 0^{- 16}$ at $2 5^{\circ} C$ , $[H_{2} S] = 0.1M$ in solution, $K_{a1} \times K_{a2} (H_{2} S) = 1.0 \times 1 0^{- 21}$ , $lo g 2 = 0.30$ , $lo g 3 = 0.48$ , $lo g 5 = 0.70$ )
Show answer
Answer: 4
Q512026 · 23 Jan 2026 · Shift 1
Consider the general reaction given below at 400 K $x A (g) ⇌ y B (g)$ . The values of $K_{p}$ and $K_{c}$ are studied under the same condition of temperature but variation in $x$ and $y$ . (i) $K_{p} = 85.87$ and $K_{c} = 2.586$ appropriate units (ii) $K_{p} = 0.862$ and $K_{c} = 28.62$ appropriate units The values of $x$ and $y$ in (i) and (ii) respectively are :
1. A.(i) 1, 2; (ii) 2, 1
2. B.(i) 1, 3; (ii) 2, 1
3. C.(i) 3, 1; (ii) 3, 1
4. D.(i) 4, 1; (ii) 4, 1
Show answer
Answer: A
Q632026 · 23 Jan 2026 · Shift 1
1. A.208
2. B.228
3. C.146
4. D.301
Show answer
Answer: B
Q722026 · 23 Jan 2026 · Shift 1· Numerical answer
For the following gas phase equilibrium reaction at constant temperature, $NH_{3} (g) ⇌ 1/2 N_{2} (g) + 3/2 H_{2} (g)$ if the total pressure is $3 atm$ and the pressure equilibrium constant ( $K_{p}$ ) is $9 atm$ , then the degree of dissociation is given as $(x \times 1 0^{- 2})^{- 1/2}$ . The value of $x$ is ____ . (nearest integer)
Show answer
Answer: 125
Q682026 · 23 Jan 2026 · Shift 2
It is noticed that $Pb^{2 +}$ is more stable than $Pb^{4 +}$ but $Sn^{2 +}$ is less stable than $Sn^{4 +}$ . Observe the following reactions. $PbO_{2} + Pb \to 2 PbO; Δ_{r} G^{\circ} (1)$ $SnO_{2} + Sn \to 2 SnO; Δ_{r} G^{\circ} (2)$ Identify the correct set from the following
1. A. $Δ_{r} G^{\circ} (1) > 0; Δ_{r} G^{\circ} (2) < 0$
2. B. $Δ_{r} G^{\circ} (1) < 0; Δ_{r} G^{\circ} (2) > 0$
3. C. $Δ_{r} G^{\circ} (1) < 0; Δ_{r} G^{\circ} (2) < 0$
4. D. $Δ_{r} G^{\circ} (1) > 0; Δ_{r} G^{\circ} (2) > 0$
Show answer
Answer: B
Q582026 · 22 Jan 2026 · Shift 1
1. A.I < II < III < IV
2. B.II < I < III < IV
3. C.III < I < II < IV
4. D.IV < III < II < I
Show answer
Answer: B
Q672026 · 22 Jan 2026 · Shift 1
A first row transition metal $(M)$ does not liberate $H_{2}$ gas from dilute HCl .1 mol of aqueous solution of $MS O_{4}$ is treated with excess of aqueous KCN and then $H_{2} S (g)$ is passed through the solution. The amount of MS (metal sulphide) formed from the above reaction is ____ mol.
1. A.1
2. B.2
3. C.0
4. D.3
Show answer
Answer: C
Q692026 · 22 Jan 2026 · Shift 1
1. A.
2. B.
3. C.
4. D.
Show answer
Answer: A
Q732026 · 22 Jan 2026 · Shift 1· Numerical answer
Dissociation of a gas $A_{2}$ takes place according to the following chemical reaction. At equilibrium, the total pressure is 1 bar at 300 K . $A_{2} (g) ⇌ 2 A (g)$ The standard Gibbs energy of formation of the involved substances has been provided below: $Substance A_{2} A Δ G_{f}^{\circ} /kJ mo l^{- 1} - 100.00 - 50.832$ The degree of dissociation of $A_{2} (g)$ is given by $(x \times 1 0^{- 2})^{1/2}$ where $x =$ ____. (Nearest integer). [ Given : $R = 8 J mo l^{- 1} K^{- 1}, lo g 2 = 0.3010, lo g 3 = 0.48$ ] Assume degree of dissociation is not negligible.
Show answer
Answer: 33
Q512026 · 21 Jan 2026 · Shift 1
Consider the following reactions. $(Hot solution) PbC l_{2} + K_{2} Cr O_{4} \to A + 2 KCl$ $A + NaOH ⇌ B + N a_{2} Cr O_{4}$ $PbS O_{4} + 4 C H_{3} COON H_{4} \to (N H_{4})_{2} S O_{4} + X$ In the above reactions, A, B and X are respectively.
1. A. $N a_{2} [Pb (OH)_{2}], PbCr O_{4}$ and $[Pb (N H_{3})_{4}] S O_{4}$
2. B. $N a_{2} [Pb (OH)_{2}], PbCr O_{4}$ and $(N H_{4})_{2} [Pb (C H_{3} COO)_{4}]$
3. C. $PbCr O_{4}, N a_{2} [Pb (OH)_{4}]$ and $(N H_{4})_{2} [Pb (C H_{3} COO)_{4}]$
4. D. $PbCr O_{4}, N a_{2} [Pb (OH)_{4}]$ and $[Pb (N H_{3})_{4}] S O_{4}$
Show answer
Answer: C
Q572026 · 21 Jan 2026 · Shift 1
Given below are two statements : Statement I : The number of pairs among $[Si O_{2}, C O_{2}], [SnO, Sn O_{2}], [PbO, Pb O_{2}]$ and $[GeO, Ge O_{2}]$ , which contain oxides that are both amphoteric is 2 . Statement II : $B F_{3}$ is an electron deficient molecule, can act as a Lewis acid, forms adduct with $N H_{3}$ and has a trigonal planar geometry. In the light of the above statements, choose the correct answer from the options given below :
1. A.Both Statement I and Statement II are false
2. B.Statement I is false but Statement II is true
3. C.Both Statement I and Statement II are true
4. D.Statement I is true but Statement II is false
Show answer
Answer: C
Q602026 · 21 Jan 2026 · Shift 1
1. A.C and E only
2. B.D and E only
3. C.A and D only
4. D.B and C only
Show answer
Answer: B
Q562026 · 21 Jan 2026 · Shift 2
$Nitrobenzene (1) B r_{2} /FeB r_{3} /Δ (2) Sn/HCl /Δ (3) pH neutralisation (4) B r_{2} / H_{2} O (5) NaN O_{2} /HBr, 0 - 5^{\circ} C (6) CuBr/NaBr Major Product (P)$ Consider the above sequence of reactions. The number of bromine atom(s) in the final product (P) will be :
1. A.6
2. B.5
3. C.1
4. D.3
Show answer
Answer: B
Q682026 · 21 Jan 2026 · Shift 2
The correct order of reactivity of the following benzyl halides towards reaction with KCN is : a: 4-hydroxybenzyl bromide $(BrC H_{2} - C_{6} H_{4} - OH$ , para $)$ b: 4-aminobenzyl bromide $(BrC H_{2} - C_{6} H_{4} - N H_{2}$ , para $)$ c: 4-nitrobenzyl bromide $(BrC H_{2} - C_{6} H_{4} - N O_{2}$ , para $)$ d: 3-nitrobenzyl bromide $(BrC H_{2} - C_{6} H_{4} - N O_{2}$ , meta $)$
1. A.a > b > c > d
2. B.b > a > d > c
3. C.b > a > c > d
4. D.a > b > d > c
Show answer
Answer: B
Q752026 · 21 Jan 2026 · Shift 2· Numerical answer
MX is a sparingly soluble salt that follows the given solubility equilibrium at 298 K. $MX (s) ⇌ M^{+} (aq) + X^{-} (aq); K_{sp} = 1 0^{- 10}$ If the standard reduction potential for $M^{+} (aq) + e^{-} \to M (s)$ is $(E_{M^{+} /M}^{⊖}) = 0.79 V$ , then the value of the standard reduction potential for the metal/metal insoluble salt electrode $E_{X^{-} /MX (s) /M}^{⊖}$ is ____ mV. (nearest integer) [Given: $\frac{2.303 R T}{F} = 0.059$ V]
Show answer
Answer: 200