Question

Explain :

BeH₂ molecules has zero dipole moment although the Be - H bonds are polar .

Answer 1

Answer:

$explanation \: .$

The Be H2 molecule is linear with ( H - be - h ) bond angle equal to 180°.

so, the Be - h bonds are polar due to the difference in the electronegravities of Be and H atom , the bonds Polarities cancel each other .

As a result the resultant dipole moment is zero .

Answer 2

Dipole moment is a vector. We know, Vectors if of equal magnitude and in opposite direction result in null vector.

Dipole moment is defined as the Product of magnitude of charges and the Distance between the charged.

µ = δ × d

In BeH2 molecule, There are two bonds between Hydrogen and Beryllium. The electronegativities of Be, H are 1.57, 2.2 respectively. So, Dipole moment is towards H atoms.

To have maximum stability, They are arranged at 180° as linear shape.

As BeH2 involves linear shape, The bond dipoles cancel each other and gives resultant dipole moment as 0.