Chemical & Ionic Equilibrium JEE Mains Previous Year Questions with Solutions and weightage

Question 1:

Solubility of calcium phosphate (molecular mass, \(M\)) in water is \(W_g\) per 100 mL at 25°C. Its solubility product at 25°C will be approximately: [JEE Main 2024]

A. \( 10^7 \left( \frac{W}{M} \right)^3 \)
B. \( 10^7 \left( \frac{W}{M} \right)^5 \)
C. \( 10^3 \left( \frac{W}{M} \right)^5 \)
D. \( 10^5 \left( \frac{W}{M} \right)^5 \)

Question 2:

At \(-20^\circ C\) and 1 atm pressure, a cylinder is filled with an equal number of \(H_2\), \(I_2\), and \(HI\) molecules for the reaction:

\[ H_2(g) + I_2(g) \rightleftharpoons 2HI(g) \]

The \(K_P\) for the process is \(x \times 10^{-1}\).
(x = ________)
Given: \(R = 0.082 \, \text{L atm K}^{-1} \text{mol}^{-1}\) [JEE Main 2024]

A. 2
B. 1
C. 10
D. 0.01

Question 3:

Given below are two statements:

Statement I: On passing \( \text{HCl(g)} \) through a saturated solution of \( \text{BaCl}_2 \), at room temperature white turbidity appears.

Statement II: When \( \text{HCl(g)} \) gas is passed through a saturated solution of \( \text{NaCl} \), sodium chloride is precipitated due to the common ion effect.

In the light of the above statements, choose the most appropriate answer from the options given below: [JEE Main 2024]

A. Statement I is correct but Statement II is incorrect
B. Both Statement I and Statement II are incorrect
C. Statement I is incorrect but Statement II is correct
D. Both Statement I and Statement II are correct

Question 4:

The equilibrium \( \text{Cr}_2 \text{O}_7^{2-} \rightleftharpoons 2 \text{CrO}_4^{2-} \) is shifted to the right in: [JEE Main 2024]

A. an acidic medium
B. a basic medium
C. a weakly acidic medium
D. a neutral medium

Question 5:

For the given hypothetical reactions, the equilibrium constants are as follows:

\( X \rightleftharpoons Y; K_1 = 1.0 \)
\( Y \rightleftharpoons Z; K_2 = 2.0 \)
\( Z \rightleftharpoons W; K_3 = 4.0 \)

The equilibrium constant for the reaction \( X \rightleftharpoons W \) is: [JEE Main 2024]

A. 6.0
B. 12.0
C. 8.0
D. 7.0

Question 6:

The following reaction occurs in the Blast furnace where iron ore is reduced to iron metal:

\( \text{Fe}_2 \text{O}_3(s) + 3 \text{CO}(g) \rightleftharpoons 2 \text{Fe}(l) + 3 \text{CO}_2(g) \)

Using Le Chatelier's principle, predict which one of the following will not disturb the equilibrium. [JEE Main 2024]

A. Addition of \( \text{Fe}_2 \text{O}_3 \)
B. Addition of \( \text{CO}_2 \)
C. Removal of \( \text{CO} \)
D. Removal of \( \text{CO}_2 \)

Question 7:

The pH of an aqueous solution containing 1 M benzoic acid (\( pK_a = 4.20 \)) and 1 M sodium benzoate is 4.5. The volume of benzoic acid solution in 300 mL of this buffer solution is: [JEE Main 2024]

Question 8:

The following concentrations were observed at 500 K for the formation:

\( 2 \times 10^{-2} \, \text{M}, [\text{H}_2] = 3 \times 10^{-2} \, \text{M}, \text{and} \, [\text{NH}_3] = 1.5 \times 10^{-2} \, \text{M}. \)

The equilibrium constant for the reaction is ______. [JEE Main 2024]

Question 9:

Given below are two statements:

Statement I: Aqueous solution of ammonium carbonate is basic.

Statement II: Acidic/basic nature of salt solution of a salt of weak acid and weak base depends on \( K_a \) and \( K_b \) value of acid and the base forming it.

In the light of the above statements, choose the most appropriate answer from the options given below: [JEE Main 2024]

A. Both Statement I and Statement II are correct
B. Statement I is correct but Statement II is incorrect
C. Both Statement I and Statement II are incorrect
D. Statement I is incorrect but Statement II is correct

Question 10:

The pH at which \( \text{Mg(OH)}_2 \) \([K_{sp} = 1 \times 10^{-11}]\) begins to precipitate from a solution containing 0.10 M \( \text{Mg}^{2+} \) ions is _____. [JEE Main 2024]
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