Question

sp³ hybrid orbitals for bond formation

Answer 1

for sp3 hybridisation.
eg. ch4

First find the steric no (it is 4 in case of CH4)
Hybridization 
sp (sn=2)
sp2(sn=3)
sp3(sn=4)
sp3d(sn=5)
sp3d2(sn=6)
sn = steric no = steric number is the no of atoms bonded to the central atom of a molecule plus the number of lone pair on the central atom
This formula will be easier to find steric no:
Sn = 1/2 {no of electrons in valence shell + bonded halogen or hydrogen or monovalent atom to central atom - charge on central atom (with sign)}