Question

Dipole moment is a vector quantity and by convention it is depicted by a small arrow with tail on the negative centre and head pointing towards the positive centre. But in chemistry, presence of dipole moment is represented by the crossed arrow put on Lewis structure of the molecule. The cross is on positive end and arrow head is on negative end. From the above data, the dipole moment in $HF$ molecule may be represented as

• A.
• B.
• C.
• D.

Answer 1

Answer: (B)

Dipole moment in $HF$ molecule can be represented as :

This arrow symbolises the direction of the shift of electron density in the molecule. Note that the direction of crossed arrow is opposite to the conventional direction of dipole moment vector.