sp³d² hybridisation (octahedral geometry, square planar shape)

X = $$1 \over 2$$ (VE + MA - c + a)

For $$NO^+_2$$, X = $$1 \over 2$$ (5 + 0 - 1) = 2, so sp hybridisation

For $$NO^-_3$$, X = $$1 \over 2$$ (5 + 0 + 1) = 3, so sp² hybridisation

For $$NH^+_4$$, X = $$1 \over 2$$ (5 + 4 - 1) = 4, so sp³ hybridisation

H₂O₂, HCN and conc. CH₃COOH form intermolecular hydrogen bonding while cellulose has intramolecular hydrogen bonding.