Question

For given solution in the questions molarity can be treated as molality and solute(s) is/are nonvolatile in nature.

Given that : $K_a$ of $CH_3COOH = 10^{-5}$ ; $K_f$ = Molal depression constant $K_a$ of $HCOOH = 10^{-4}$ ; $K_b$ = Molal elevation constant

Column - I (Colligative properties)	Column - II (One of the product formed during electrolysis at Pt - electrode)	Column - III (Nature of aqueous solution at 25 C)
(I) $\Delta T_b \approx 0.3 K_b$	(A) Metal becomes deposited	(P) pH = 8.5 at cathode
(II) $\pi \approx 0.4RT$	(B) $H_2$ gas at cathode	(Q) pH = 4.7
(III) $\Delta T_f \approx 0.2 K_f$	(C) $H_2$ gas at anode	(R) pH $\approx$ 7
(IV) $\pi \approx 0.3RT$	(D) $O_2$ gas at anode	(S) Weakly basic solution

Which of the following option is correctly matched for 0.1M HCOOK (aq.)

• A. (I), (A), (P)
• B. (II), (B), (Q)
• C. (III), (C), (P)
• D. (IV), (D), (S)

Answer 1

Answer: (C)

(III), (C), (P)

Answer 2

0.1M HCOOK (aq.) will have:

• $\Delta T_f \approx 0.2 K_f$ (Molal depression constant)
• $H_2$ gas at cathode (Product formed during electrolysis at Pt - electrode)
• pH = 8.5 at cathode (Nature of aqueous solution at 25 C)