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Question
Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).
Solution
Copper is a good conductor of heat and does not react with hot water; on the contrary, iron reacts with hot water.
Copper (Cu), rather than Steel or an alloy of Iron (Fe), is used to make hot water tanks:
- Iron reacts with steam to corrode the tank, whereas copper does not react with either of these substances.
- Steam has an effect on iron, while temperature fluctuations have no effect on copper.
- When hot water produces steam, iron reacts with it in the following forms:
\[\ce{\underset{Iron}{3Fe} + \underset{Water}{4H2O} -> \underset{Ferric oxide}{Fe3O4} + \underset{Hydrogen gas}{4H2↑}}\]
Therefore, copper rather than steel is used to make hot water tanks.
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