Answer: The correct answer is Option 2.
Explanation:
For the given options:
Option 1: Hydroxide ion
The chemical formula for this ion is [tex]OH^-[/tex]
Option 2: Hydronium ion
The chemical formula for this ion is [tex]H_3O^+[/tex]
Option 3: Hypochlorite ion
The chemical formula for this ion is [tex]ClO^-[/tex]
Option 4: Perchlorate ion
The chemical formula for this ion is [tex]ClO_4^-[/tex]
For the given chemical reaction:
[tex]HCl(g)+H_2O(l)\rightarrow H_3O^+(aq.)+Cl-(aq.)[/tex]
The ion represented by X is hydronium ion.
Hence, the correct answer is Option 2.