A mercury cathode cell for brine electrolysis carries a steady current of 9650 A for 1.00 h with a current efficiency of 80.0% for sodium deposition. All the amalgam is later converted to $NaOH$ . Taking F = 96500 C/mol and M( $NaOH$ ) = 40 g/mol, the mass of $NaOH$ obtained is

Answer: C

Charge used for sodium

= 9650 \times 3600 \times 0.800 = 2.779 e + 07

C, which is 288 mol of electrons. Each

Na X^{+} + e X^{-}

gives one Na, and amalgam with water gives one

NaOH

, so 288 mol

\times 40

g = 11520 g = 11.52 kg.