Question

In the following reaction between lead sulphide and hydrogen peroxide:
$\mathrm{PbS}\left(\mathrm{s}\right)+4{\mathrm{H}}_2{\mathrm{O}}_2\left(\mathrm{aq}\right)\underset{}{\to }{\mathrm{PbSO}}_4\left(\mathrm{s}\right)+4{\mathrm{H}}_2\mathrm{O}\left(1\right)$
(a) which substance is reduced?
(b) Which substance is oxidised?

Answer 1

(a) Hydrogen peroxide (H₂O₂) is reduced.

(b) Lead sulphide (PbS) is oxidised.
This is because lead sulphide gains oxygen, while hydrogen peroxide loses oxygen.