Question

Which of the following statements is not correct regarding preparation of NaOH?

• A. NaOH is prepared by electrolysis of sodium chloride in Castner – Kellner cell.
• B. Sodium metal discharged at cathode combines with mercury to form sodium amalgam.
• C. Chlorine is evolved at anode.
• D. Amalgam is heated to separate Na and Hg.

Answer 1

Answer: (D)

Amalgam is heated to separate Na and Hg.

Answer 2

: Amalgam is treated with water to give sodium hydroxide and hydrogen gas.

$2Na - ama\lg am + 2H_{2}O \rightarrow 2NaOH + 2Hg + H_{2}$