Question

In which of the following types of reactions are electrons gained?

Answer 1

1) It must be oxidized
2) reduction
3) Sodium
4) Hydrogen

Answer 2

Answer: The correct answer for 1 is Option 4 and for 2 is Option 1.

Explanation:

• For 1:

From the given options:

Decomposition reaction is defined as the reaction in which a compound breaks down into two or more smaller compounds.

Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance is increased.

Neutralization reaction is defined as the reaction in which an acid reacts with a base to produce a salt and water molecule.

Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.

From the above information, the correct answer is Option 4.

• For 2:

Reducing agent is defined as the agent which reduces the other substance and itself gets oxidized. It undergoes oxidation reaction.

Oxidizing agent is defined as the agent which oxidizes the other substance and itself gets reduced. It undergoes reduction reaction.

The reaction of sodium and oxygen follows the equation:

$4Na(s)+O_2(g)\rightarrow 2Na_2O(s)$

On reactant side:

Oxidation state of sodium = 0

Oxidation state of oxygen = 0

On product side:

Oxidation state of sodium = +1

Oxidation state of oxygen = -2

As, the oxidation state of sodium is increasing from 0 to +1, it is undergoing an oxidation reaction and thus is a reducing agent. While the oxidation state of oxygen is reducing from 0 to -2, it is undergoing an reduction reaction and thus is a oxidizing agent.

Hence, the correct answer is Option 1.