Define redox reaction?

There are two types of Redox reactions

• Direct Redox reaction
• Indirect Redox reaction

Direct Redox reaction: In which oxidation and reduction both occur in same beaker. In this electron so produced does not travel to large distance.

For example: A beaker containing Zinc rod dipped in Copper sulphate solution in this the following reaction occur:

Zn    +    CuSO₄ -->       ZnSO₄ + Cu

Zinc   CopperSulphate  Zinc Sulphate  Copper

In this zinc being more reactive displaces copper from copper sulphate and forms zinc sulphate and copper.

Indirect Redox reactions: In it oxidation and reduction occur in different beakers. The electron so produced has to travel a certain distance that leads to generation of current.

Example: Daniel cell: A cell containing Zn-Cu couple that we are going to study in detail now as given below but before that let us make you familiar with the general term used in redox reaction that is Redox couple.