Explain why `BeH_(2)` molecule has a zero dipole moment although the `Be-H` bonds are polar?

Explanation

The Lewis structure for `BeH_(2)` is as follows:
`H:Be:H`
There is no lone pair at the central atom (Be) and there are two bond pairs. Hence, `BeH_(2)` is of the type `AB_(2)`. It has a linear structure.

Dipole moments of each H-Be bond are equal and are in opposite directions. Therefore, they nullify each other. Hence , `BeH_(2)` molecule has zero dipole moment.