Which of the following does not have a triple bond between the atoms?

The potential energy curve for the $H_2$ molecule as a function of internuclear distance is:

$AlCl_3$,in reactions,acts as

Which of the following molecules does not obey the octet rule?

In which of the following molecules are $\pi-$ electrons not delocalized?

The $B-F$ bond dissociation energy in $BF_3$ is $646 \ kJ \ mol^{-1}$,whereas the $C-F$ bond dissociation energy in $CF_4$ is $515 \ kJ \ mol^{-1}$. Which of the following is the correct reason for the $B-F$ bond dissociation energy being higher than the $C-F$ bond dissociation energy?