Answer:
b. CHâ‚‚Clâ‚‚ is more volatile than CHâ‚‚Brâ‚‚ because of the large dispersion forces in CHâ‚‚Brâ‚‚
Explanation:
CH₂Cl₂ is more volatile than CH₂Br₂ (b.p of CH₂Cl₂ = 39,6 °C; b.p of CH₂Br₂ = 96,95°C). Thus, c. and d. are FALSE
Dipole-dipole interactions in CHâ‚‚Clâ‚‚ are greater than the dipole-dipole interactions in CHâ‚‚Brâ‚‚ because Cl is more electronegative that Br (Cl = 3,16; Br = 2,96). But this mean CHâ‚‚Clâ‚‚ is less volatile than CHâ‚‚Brâ‚‚ but it is false.
There are large dispersion forces in CHâ‚‚Brâ‚‚ because Br has more electrons and protons than Cl. Large disperson forces mean CHâ‚‚Brâ‚‚ is less volatile than CHâ‚‚Clâ‚‚ and it is true.
I hope it helps!