Question

Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).

Answer 1

Copper, rather than steel or an alloy of iron, is used to make hot water tanks because copper does not react with either water or steam, while iron reacts with steam to corrode the tank.

1. Copper is unaffected by cold water, hot water, or steam, whereas iron is influenced by steam.
2. Iron would react with steam produced by hot water if water tanks were made of steel, which is an iron alloy.

$\underset{\mathrm{Iron}}{3\mathrm{Fe}}+\underset{\mathrm{Water}}{4{\mathrm{H}}_2\mathrm{O}}\to \underset{\mathrm{Iron}\mathrm{Oxide}}{{\mathrm{Fe}}_3{\mathrm{O}}_4}+\underset{\mathrm{Hydrogen}}{4{\mathrm{H}}_2}$