Question

During the presence of $S{O}_3^{2-}$ and $S^{2-}$ in a mixture, with addition of $dil.H_{2}S{O}_4$, one can notice :

• A. $S{O}_2$ and $H_{2}S$ are not formed.
• B. $S{O}_2$ and $H_{2}S$ formed undergo a redox change forming colloidal sulphur and thus no smell
• C. a smell of rotten egg
• D. a smell of burning sulphur

Answer 1

Answer: (B)

$S{O}_2$ and $H_{2}S$ formed undergo a redox change forming colloidal sulphur and thus no smell

And these formed gases undergo redox changes forming colloidal sulphur and thus no smell.
$S{O}_2+H_{2}S\to 2S$
+4 -2 0