The number of $sp^{2}$ hybrid orbitals in a molecule of benzene is

The hybridisation of $C$ in diamond,graphite and ethyne is in the order

Which pair of molecules has different hybridisation but the same shape?

Choose the molecules in which hybridization occurs in the ground state?
$(i)$ $BCl_3$ $(ii)$ $NH_3$
$(iii)$ $PCl_3$ $(iv)$ $BeF_2$
The correct answer is

Why is the bond angle in $CH_4$ not $90^{\circ}$,even though the outermost $p$-orbitals of carbon are at $90^{\circ}$ to each other?

The shape of methane molecule is