What effect does branching of an alkane chain has on its boiling point?

Which of the following has the highest boiling point ? i. 2-Methyl pentane ii. 2,3-Dimethyl butane iii. 2,2-Dimethyl butane b. What effect does branching of an alkane chain has on its melting point ?

What effect the branching of an alkane has on its boiling point?

Which has highest boiling point