Reactions of Alcohols

Many alcohols are colourless liquids that are soluble in water and form neutral solutions. As the number of carbon atoms in an alcohol increases, its solubility in water decreases. The first four alcohols are often used as fuels. Also, methanol and ethanol are widely used as solvents.

Combustion of Alcohols

Alcohols undergo complete combustion in the presence of oxygen to form carbon dioxide and water. This means that we can use them as a source of energy. For example, the combustion of ethanol:

Ethanol + Oxygen Carbon dioxide + Water

C2H5OH + 3O2 2CO2 + 3H2O

When combusted, alcohols release energy.

Reactions With Sodium

Alcohols react with sodium to form hydrogen gas and a metal salt. For example, when ethanol reacts with sodium, bubbles of hydrogen gas are produced, and sodium ethoxide is formed.

Ethanol + Sodium Sodium ethoxide + Hydrogen

2Na + 2C2H5OH 2C2H5ONa + H2

Oxidation of Alcohols

Alcohols can be chemically oxidised without combustion to produce carboxylic acids, which are organic acids. For example, ethanol can be oxidised to ethanoic acid using an oxidising agent.

Ethanol + Oxidising Agent Ethanoic acid + Water

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