Question

what is oxidition and reduction

Answer 1

oxidation was first used for a reaction in which oxygen is combined with the substance while reduction was first used for a reaction in which oxygen was removed from a substance.

Answer 2

The reaction involving the loss of hydrogen atoms and addition of oxygen atoms is called oxidation reaction. Example :
             2 Cu + O₂ ------------>  2 CuO [addition of oxygen]
             H₂S + Cl₂ ------------->  2 HCl + S [removal of hydrogen]
The reaction involving the loss of oxygen atoms and addition of hydrogen atoms is called reduction reaction. Example :
             CuO + H₂ --------------> Cu + H₂O [removal of oxygen]
             Cl₂ + H₂S --------------> 2 HCl + S [addition of hydrogen].