What are the shapes of $sp$,$sp^2$,and $sp^3$ hybrid orbitals?

Which of the following compounds exhibits $sp^2$ hybridization?

In which of the following molecules,the number of lone pairs of electrons on the central atom and the number of $d$-orbitals involved in the hybridisation of the central atom are the same?

The structures of $BCl_3$ and $BCl_3 \cdot NH_3$,respectively are

Find the incorrect statement.

Explain the formation of bonds using $sp^2$ hybrid orbitals with an example.