Statement I: Dipole moment is a vector quantity and by convention it is depicted by a small arrow with tail on the…

🧠 Two separate conventions exist for dipole moment arrows. Statement I describes the physics convention (tail at −, head at +), but in chemistry the crossed arrow convention places the cross at the positive end and the arrowhead at the negative end (showing electron drift direction). These two are opposite, making Statement I incorrect.

Statement I — Incorrect: In chemistry convention, the arrow tail (cross, $\oplus$) is at the positive centre and the head points toward the negative centre. Statement I reverses this.

Statement II — Correct: The crossed arrow ($\rightarrow$ with cross at tail) represents the direction of electron density shift — from the less electronegative atom (positive partial charge) toward the more electronegative atom (negative partial charge). This symbolises the shift of the negative charge within the molecule.

⚠️ Trap: The physics convention and the chemistry convention are exactly opposite. JEE always tests the chemistry (crossed arrow) convention, not the physics one.

$\boxed{\text{Answer: (b) Statement I is incorrect but Statement II is correct}}$