Question

Determine which substance is oxidized and which substance is reduced in the following reaction:
${\text{CO}}_2\text{(g)}+{\text{H}}_2\text{(g)}\to \text{CO(g)}+{\text{H}}_2\text{O(g)}$

• A. ${\text{CO}}_2$ is oxidized and ${\text{H}}_2$ is reduced.
• B. ${\text{CO}}_2$ is reduced and ${\text{H}}_2$ is oxidized.
• C. Both ${\text{CO}}_2$ and ${\text{H}}_2$ are reduced.
• D. Both ${\text{CO}}_2$ and ${\text{H}}_2$ are oxidized.

Answer 1

The correct option is B ${\text{CO}}_2$ is reduced and ${\text{H}}_2$ is oxidized.

A substance is said to be oxidised if it either gains oxygen atom or loses hydrogen atom.

A substance is said to be reduced if it either loses oxygen atom or gains hydrogen atom.

In the given chemical reaction, ${\text{CO}}_2$ is reduced since it is losing oxygen atom and ${\text{H}}_2$ is oxidized since it is gaining oxygen atom.