Definitions of Oxidation and Reduction

Question 1

oxygen

Answer 1

Oxidation is the gain of oxygen by a substance in a chemical reaction
Reduction is the loss of oxygen by a substance in a chemical reaction

Question 2

hydrogen

Answer 2

Oxidation is the loss of hydrogen by a substance in a chemical reaction
Reduction is the gain of hydrogen by a substance in a chemical reaction

Question 3

electrons

Answer 3

Oxidation is the loss of electrons by a substance in a chemical reaction
Reduction is the gain of electrons by a substance in a chemical reaction

Question 4

oxidation state

Answer 4

Oxidation involves increase in oxidation number of an element
Reduction involves decrease in oxidation number of an element