Question

A 4.0 molar aqueous solution of NaCI is prepared and 500 mL of this solution is electrolysed.This leads to the evolution of chlorine gas at one of the electrodes. If the cathode is a Hg electrode, the maximum weight (g) of amalgam formed from this solution is: (atomic mass : Na =23, Hg = 200)

• A. 200
• B. 225
• C. 400
• D. 446

Answer 1

The correct option is D 446

Number of moles of $N{a}^{+}$ reduced at cathode $=\frac{MV}{1000}=\frac{4\times 500}{1000}=2$
Mass of amalgam = Mass of 2 mol $Na$ + Mass of 2 mol $Hg$
$=2\times 23+2\times 200=446g$