Question

The addition of hydrogen to a substance is called ______ whereas removal of hydrogen is called ______.

Answer 1

The addition of hydrogen to a substance is called reduction whereas removal of hydrogen is called oxidation.

Explanation:

The reactions are classified by the movement of hydrogen atoms. When a substance gains hydrogen, it undergoes reduction, which typically decreases its oxidation state. Conversely, when a substance loses hydrogen, it undergoes oxidation, which increases its oxidation state.