JEE Main 2025 Jan 22 Shift 1, Chemistry Q1: Electrolytic Cells And Electrolysis

JEE Main2025Jan 22, Shift 1Chemistry

A solution of aluminium chloride is electrolysed for 30 minutes using a current of 2A. The amount of the aluminium deposited at the cathode is ___ .

[Given : molar mass of aluminium and chlorine are 27 g mol $^{- 1}$ and 35.5 g mol $^{- 1}$ respectively, Faraday constant = 96500 C mol $^{- 1}$ ].

Solution

Charge passed: $Q = I t = 2 \times (30 \times 60) = 3600$ C.

By Faraday's law, mass deposited $w = \frac{E \cdot Q}{F}$ , where the equivalent weight of Al is $E = \frac{27}{3} = 9$ g/eq.

$w = \frac{9 \times 3600}{96500} \approx 0.336$ g.

$∴$ Mass of Al deposited $= 0.336$ g.

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