Question

Arrange the following compounds in-decreasing order of their boiling points
(i) $C{H}_{3}Br$
(ii) $C{H}_{3}C{H}_{2}Br$
(iii) $C{H}_{3}C{H}_{2}C{H}_{2}Br$
(iv) $C{H}_{3}C{H}_{2}C{H}_{2}C{H}_{2}Br$

• A. (i) > (ii) > (iii) > (iv)
• B. (iv) > (iii) > (ii) > (i)
• C. (i) > (iii) > (ii) > (iv)
• D. (iii) > (iv) > (i) > (ii)

Answer 1

The correct option is B (iv) > (iii) > (ii) > (i)

Intermolecular forces of attractions increases as​ molecular size increases.​ So, large amount​ of heat require to break strong intermolecular forces​ and thus boiling point increases. Here, the order of molecular size is as follows:
(iv) > (iii) > (ii) > (i)
So, the boiling point order will be the same.
Hence, the correct answer is option (b).