Explain why BeH2 molecule has a zero dipole moment although the Be–H bonds are polar.
BeH2is a linear molecular (H—Be—H), the bond angle = 180°.
Be—H bonds are polar due to a difference in their electronegativity but the bond polarities cancel each other. Thus, molecule has resultant dipole moment of zero
The Lewis structure for BeH2 is as follows:
There is no lone pair at the central atom (Be) and there are two bond pairs. Hence, BeH2 is of the type AB2. 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, BeH2 molecule has zero dipole moment.
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