(a) What effect the branching of an alkane has on its melting point? (L-III) (b) Which of the following has highest boiling point?(L-III) (1) 2-methyl pentane. (2) 2, 3-diethyl butane. (3) 2, 2- dimethyl butane.

(a) What effect the branching of an alkane has on its melting point? (L-III)
 (b) Which of the following has highest boiling point?(L-III)
 (1) 2-methyl pentane.
 (2) 2, 3-diethyl butane.
 (3) 2, 2- dimethyl butane.
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1 Answer

Answer :

Ans.(a) In general conception, as the branching increases packing of the molecules in the crystals becomes less close and have melting point decreases accordingly. (b) As the branching increases, surface area decreases and thus magnitude of Vander Waals forces of attraction decreases and hence the boiling point decreases. So, 2-methyl pentane has highest B.pt.
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