Question

What is the correct relation between boiling points of the following alkyl iodides, where R=methyl, R’=ethyl and R”=propyl?

(a) RI > R’I > R”I

(b) R”I > R’I > RI

(c) RI = R’I = R”I

(d) R”I = R’I > RI

I have been asked this question in homework.

This intriguing question originated from Haloarenes Physical Properties in division Haloalkanes and Haloarenes of Chemistry – Class 12

Answer 1

Correct answer is (b) R”I > R’I > RI

Easiest explanation: The forces of attraction become stronger as the molecules getter bigger in size and number of electrons increases. Hence, the methyl halides will have the lowest boiling points among all alkyl groups.