The X must be sodium hydroxide (NaOH) because of the following reactions:

i. When NaOH reacts with zinc (a metal), it gives sodium zincate (a salt) and hydrogen gas:

ii. When sodium hydroxide (a base) and HCl (an acid) reacts together, they form a common salt (NaCl) and water:

NaOH + HCl → NaCl + H₂O

Note: The above reaction is a neutralization reaction. The reaction

between an acid and a base to give a salt and water is called neutralization reaction.

Base + Acid → Salt + Water

iii. When NaOH and CH₃COOH (an acid) reacts together, they form a salt of sodium acetate and water:

The above reaction is also an example of neutralization reaction.

Thus, X is NaOH.

A is sodium zincate (Na₂ZnO₂)

B is common salt (NaCl)

C is sodium acetate (CH₃COONa)