Name the reducing agent in the following reaction:

$3{\mathrm{MnO}}_2+4\mathrm{Al}\to 3\mathrm{Mn}+2{\mathrm{Al}}_2{\mathrm{O}}_3$

State which is more reactive, Mn or Al and why?

When a metal X is treated with a dilute acid Y, then a gas Z is evolved which burns readily by making a little explosion.

(a) Name any two metals which can behave like metal X.

(b) Name any two acids which can behave like acid Y.

(c) Name gas Z.

(d) Is the reaction between metal X and dilute acid Y exothermic or endothermic.

In the following reaction between lead sulphide and hydrogen peroxide:

$\mathrm{PbS}\left(\mathrm{s}\right)+4{\mathrm{H}}_2{\mathrm{O}}_2\left(\mathrm{aq}\right)\to {\mathrm{PbSO}}_4\left(\mathrm{s}\right)+4{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

Name the substance reduced and oxidised.