Question

How to balance this redox reaction using half-reaction method: Ni(s) + HCl(s)->NiCl2(s) + H2(s)

Answer 1

Half reaction to each product;

Ni + 2Cl^- $\implies$ NiCl₂

2H⁺ $\implies$ H_2(g)

Full balanced reaction.

Ni_(s) + 2HCl_(g) $\implies$ NiCl_2(s) + H_2(g)