Statement I: 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.
Statement II: The crossed arrow of the dipole moment symbolizes the direction of the shift of charges in the molecules.
In the light of the above statements, choose the most appropriate answer:

Analysis of Statement I

Statement I states that dipole moment is a vector quantity and is represented by a small arrow with its tail on the negative centre and head pointing towards the positive centre.

Although dipole moment is indeed a vector quantity, the direction of the dipole moment vector is stated incorrectly.

By convention, the dipole moment vector points from the positive centre to the negative centre, i.e., the tail is at the positive end and the head points towards the negative end.

Hence, Statement I is incorrect.

Analysis of Statement II

Statement II states that the crossed arrow of the dipole moment symbolizes the direction of the shift of charges in the molecule.

This is correct. The crossed arrow represents the direction of electron density shift, pointing from the partial positive charge $$\delta^+$$ towards the partial negative charge $$\delta^-$$.

Hence, Statement II is correct.

Conclusion

• Statement I is incorrect.
• Statement II is correct.

Therefore, the correct answer is

$$\boxed{\text{Option B: Statement I is incorrect but Statement II is correct.}}$$