The aqueous solution of $ZnSO_4, AgNO_3, FeCl_3$ and $WCl_6$ are electrolyzed for 2 hours using a current of 5 amperes. The decreasing order of mass deposited of the following metals at cathode will be.........

(A) Zn
(B) Ag
(C) Fe
(D) W
(atomic mass: $Fe =56\, g\, mol^{-1}, Zn =65\, g\, mol^{-1}, Ag = 108\, g\, mol^{-1}, W = 184\, g\, mol^{-1}$)

Choose the correct answer from the options given below:

(B), (A), (D), (C)

The correct answer is Option (3) → (B), (A), (D), (C)

From Faraday’s Law: Mass deposited ∝ Equivalent weight

Equivalent weight = Atomic mass / Valency

At cathode:

Ag⁺ → Ag (valency = 1)

Zn²⁺ → Zn (valency = 2)

Fe³⁺ → Fe (valency = 3)

W⁶⁺ → W (valency = 6)

Calculate equivalent weights:  Atomic mass / Valency

• Zn: 65 / 2 = 32.5
• Ag: 108 / 1 = 108
• Fe: 56 / 3 ≈ 18.67
• W: 184 / 6 ≈ 30.67

Mass deposited ∝ M/n, so decreasing order:

$\text{Ag > Zn > W > Fe}$

 (B), (A), (D), (C)