Define oxidising and reducing agents by giving suitable example.

$Oxidizingagent$ 

$\text{: An oxidizing agent is an element that gains electrons. Since the oxidizing agent means to}$ $\text{gain electrons; it is said to have been reduced.}$

$\text{The element which undergoes reduction (gets reduced) is called an oxidizing agent.}$

For example: $2Mg+O_2\to 2MgO$

$\text{In the given reaction,}$ $O_2$ $\text{is reduced by losing oxygen atoms. Thus,}$ $O_2$ $\text{is an oxidizing agent as it undergoes reduction.}$

$Reducingagent:$ 

$\text{A reducing agent is an element that loses electrons. The reducing agent means to lose}$ $\text{electrons; it is said to have been oxidized.}$

$\text{The element which undergoes oxidation (gets oxidized) is called the reducing agent.}$ 

For example:

$4N{H}_3+5O_2\to 4NO+6H_{2}O$

$\text{In the given reaction, nitrogen is oxidized to}$ $NO$ $\text{by gaining oxygen atom. Thus,}$ $N{H}_3$ $\text{is reducing agent as it undergoes oxidation.}$