In this question, X denotes an atom of chlorine, bromine or iodine. Which explanation of the change in volatility down Group 17 is correct?
- AInstantaneous dipole-induced dipole forces between molecules become stronger.
- BPermanent dipole-permanent dipole forces between molecules become stronger.
- CThe bond energy of the $\text{X}_2$ molecules decreases.
- DThe first ionisation energy $\text{X}(g) \rightarrow \text{X}^+(g) + e^-$ decreases.