Question

Give reasons:

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

Answer 1

Copper (Cu), rather than Steel or an alloy of Iron (Fe), is used to make hot water tanks:

• Copper does not react with water or steam, while Iron reacts with steam to corrode the tank.
• Copper is unaffected by temperature changes, whereas iron is influenced by steam.
• Iron would react with steam produced by hot water, and the reaction proceeds as follows:

$\underset{\mathrm{Iron}}{3\mathrm{Fe}}+\underset{\mathrm{Water}}{4{\mathrm{H}}_2\mathrm{O}}\to \underset{\mathrm{Ferric}\mathrm{oxide}}{{\mathrm{Fe}}_3{\mathrm{O}}_4}+\underset{\mathrm{Hydrogen}\mathrm{gas}}{4{\mathrm{H}}_2\uparrow }$

Thus, copper is used for making hot water tanks and not steel.