Răspuns:
HgS + HNO3 + HCl = HgCl2 + S + NO + H2O
Hg+²S-²
H+¹N+⁵O3‐²
H+¹Cl ‐¹
Hg+²Cl2-¹
S⁰
N+²O-²
H2+¹O-²