K(s) + SnCl₂(aq) → K⁺(aq) + Sn(s) + Cl^–(aq) (pH = 1)

oxidation/reduction under acidic conditions

[K(s) → K⁺(aq) + e^–] × 2

SnCl₂(aq) + 2 e^– → Sn(s) + 2 Cl^–(aq)

2 K(s) + SnCl₂(aq) → 2 K⁺(aq) + Sn(s) + 2 Cl^–(aq)