Question

A substace when kept in open become moist. it is made up of chlor alkali

Answer 1

X is NaOH i.e. Sodium Hydroxide. 

When electricity is passed through an aqueous solution of sodium chloride (called brine), it decomposes to form sodium hydroxide. The process is called the chlor-alkali process because of the products formed- chlor for chlorine and alkali for sodium hydroxide. Following is the chemical equation for the process-

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

When NaOH is treated with HCl, NaCl is formed.

NaOH + HCl → NaCl + H2O