A day has 24 hours.

Organic solvents play an important role in chemical reactions.

He ate one apple.

Calcium carbide is a major raw material for acetylene gas.

It is important for each person to fulfill their role.

Hydrogen sulphide is extremely toxic, and particularly at high concentrations, it is lethal to humans.

He hydrogenated fatty acids in a chemical experiment.

This compound is stabilized by hydrogenation.

He was involved in the development of the hydrogen bomb.

He acted according to my instructions one by one.