Acids, Bases & Salts (C10)

How is sodium hydroxide manufactured in industries ? Name the process. In this process a gas X is formed as by-product. This gas reacts with lime water to give a compound Y, which is used as a bleaching agent in the chemical industry. Identify X and Y and write the chemical equation of the reactions involved.

Answer

When electricity is passed through an aqueous solution of sodium chloride (brine).

Chlor - alkali process

X: Cl2

Y: CaOCl2

2NaCl (aq) + 2H2O (l) → 2NaOH (aq) + Cl2 (g) + H2 (g)

Ca(OH)2 + Cl2 → CaOCl2 + H2O