Sir can you please explain me Drago's Rule related to 
hybridyzation of compounds ? Sir please keep your explanation 
as brief as possible.

Dear abhinav,

Drago s rule is :

For any Group in general,the formula for calculating the number of hybrid orbitals is group number of central element + no.of atoms sorrounding the central element(except oxygen)-charge on the central element(consider the charge including its sign) whole divided by 2.