how does ozone react with acidic ferrous sulphate solution and with mercury?

1. Ferrous Sulphate (FeSO₄) _​is oxidised to ferric sulphate [Fe₂(SO₄)₃]

$$\begin{gathered} O_3 \to O_2 + O \\ 2 FeS{O}_{4 } + H_{2}S{O}_4 + O \to F{e}_2(S{O}_4{)}_3 + H_{2}O \\ ------------------------- \\ 2 FeS{O}_{4 } + H_{2}S{O}_4 +O_3 \to F{e}_2(S{O}_4{)}_3 + H_{2}O +O_2 \\ ------------------------- \end{gathered}$$

2. Mercury (Hg) gets oxidised to mercurous oxide (Hg₂O)

$2 Hg + O_3 \to H{g}_{2}O + O_2$