Question

Why melting point and boiling point of alkanes increase as molecular weight increases

Answer 1

Do you mean alkalis?

Answer 2

no

Answer 3

it is because in higher alkanes there is greater vander Waal's force of surface area attraction than the alkanes of lower molecular masses. The increase in molecular size governs the increase in the molecules which causes rise of magnitude of vander Waal's force of attraction.

Answer 4

The boiling and melting points of the branched chain isomers are lower than their straight chain isomers due to spherical shape, there is decrement in surface area of molecules. The lower the surface area the smaller the magnitude of vander Waal's force of attraction.

Answer 5

more carbon atoms = more dispersion forces in short :)

Answer 6

yea. Ok thanks :D

Answer 7

Your welcome!