Aqueous $NiSO X_{4}$ and aqueous $CrCl X_{3}$ are electrolysed in two cells connected in series. When $5.87 g$ of nickel is deposited in the first cell, the mass of chromium deposited in the second cell is (Ni = 58.7, Cr = 52)

Answer: B

Same charge through both cells. Nickel:

5.87/58.7 = 0.100 mol

, needing

0.200 mol

of electrons (

Ni X^{2 +} + 2 e X^{-} Ni

). Chromium:

Cr X^{3 +} + 3 e X^{-} Cr

, so

0.200/3 = 0.0667 mol

= 0.0667 \times 52 = 3.47 g

. Option (C) wrongly uses

n = 2

for chromium.