Question

Give two examples to show the reducing property of hydrogen. Illustrate using equations.

Answer 1

Reducing property of hydrogen:

• It acts as a good reducing agent means, when hydrogen gas passed over the hot metallic oxide of copper, lead, iron, etc.
• It removes oxygen from them and reduces them to their corresponding metal.

1. Hydrogen removes oxygen:

• It removes oxygen from metal oxides, which is called a reduction reaction and hydrogen is called a reducing agent.
• Copper oxide loses its oxygen to convert copper metal.
• Hydrogen combines (taken out) with oxygen to form water.

$\underset{\mathrm{Copper}\mathrm{oxide}}{\mathrm{CuO}\left(\mathrm{s}\right)}+\underset{\mathrm{Hydrogen}}{{\mathrm{H}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{Copper}}{\mathrm{Cu}\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$

• Copper is left in the combustion tube.

2. Hydrogen reduces lead oxide into metallic lead:

• Here, hydrogen acts as a reducing agent.
• Lead(II) oxide loses its oxygen and forms solid lead metal

$\underset{\mathrm{Lead}\mathrm{oxide}}{\mathrm{PbO}\left(\mathrm{s}\right)}+\underset{\mathrm{Hydrogen}}{{\mathrm{H}}_2\left(\mathrm{g}\right)}\to \underset{\mathrm{Lead}}{\mathrm{Pb}\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}$

• Lead is left in the combustion tube.

Hence, the above two reactions are examples to show the reducing property of hydrogen.