The $H-C-H$ bond angle in $CH_4$ is

During the complete combustion of methane $CH_4$,what change in hybridisation does the carbon atom undergo?

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

Which compound of sulphur is formed in the second excited state?

Provide the orbital structure of ethene showing: $(i)$ $\sigma$-bond $(ii)$ $\pi$-bond $(iii)$ The number of $\sigma$ and $\pi$-bonds $(iv)$ The hybridization.

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