# $H_2S$ and $SO_2$ can be distinguished by

(a) Litmus paper
(b) Lime water
(c) $Pb(CH_3COO)_2$
(d) $HCl$

Answer: $Pb(CH_3COO)_2$

$Pb(CH_3COO)_2 + H_2S \longrightarrow PbS + 2CH_3COOH$
$SO_2$ has no effect on $Pb(CH_3COO)_2$.