Choose the word which is different from the rest.

Mercury
Acetone
Petrol
Kerosene

The answer is A. Mercury.

Mercury is a metal, while the other options are all liquids. Mercury is also the only option that is a liquid at room temperature.

Acetone is a colorless, flammable liquid that is used as a solvent and a paint thinner. It is also used in nail polish remover.

Petrol is a flammable liquid that is used as a fuel in cars and other engines. It is also known as gasoline.

Kerosene is a flammable liquid that is used as a fuel in jet engines and other engines. It is also known as paraffin oil.