Question

Which of the following statement is correct ?

• A. $F_2$ has higher dissociation energy than $C{l}_2$ .
• B. $F$ has higher electron affinity than $Cl$ .
• C. $HF$ is stronger acid than $HCl$ .
• D. The boiling point increases down the group in halogens.

Answer 1

Answer: (D)

(i) Bond dissociation energy of $F_2$ is less than that of $C{l}_2$ , on account of repulsion between non-bonded pairs of electrons on smaller $F$ atoms.
(ii) $Cl$ has higher electron affinity than fluorine.
(iii) $HF$ is weaker acid than $HCl$ , due to its higher bond energy.
(iv) The boiling point increases down the group in halogens on account of increasing force of attraction amongst the molecules with increasing size of the molecules ( $i.e.$ , increasing Van der waals force of attraction).