Question

(i) Explain why BF₃ molecule has zero dipole moment although the B-F bonds are polar?

(ii) Alkali metals and Halogens form Ionic compounds. Give reason.

Answer 1

(i) Shape of BF₃ is Trigonal planar.

The net sum of bond moment is equal to zero because of cancellation of bond moments due to symmetry in the molecule.

(ii) Alkali metals have low ionization enthalpy hence they easily form cations.

Halogens have high electron gain enthalpy hence they easily form Anions.