The number and type of bonds between two carbon atoms in calcium carbide are

The potential energy $(y)$ curve for $H_2$ formation as a function of internuclear distance $(x)$ of the $H$ atoms is shown below.
The bond energy of $H_2$ is

At $25\,^oC$,hydrogen chloride is:

Which of the following occurs when two hydrogen atoms bond with each other?

Which of the following has $p\pi-d\pi$ bonding?

Among $NH_3, BCl_3, Cl_2$ and $N_2$,the compound that does not satisfy the octet rule is