In a covalent bond,....................

Number of electrons in the valence orbit of nitrogen in an ammonia molecule are

Which of the following compounds is not matched correctly with its structure?

In which of the following species $p\pi - d\pi$ bond is present but $p\pi - p\pi$ bond is absent?

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

Which of the following is a non-polar bond?