how is it possible for a nonpolar molecule to have higher boiling point than a polar one.?

It is possible, but the question lies in whether the comparison is fair or not.

Example: For decane, its boiling point is 174 degree celcius. For a polar molecule, such as ethanol, it is only 78 degree celcius. But anybody will know this comparison is not fair.

If we were to carry out a fair comparison, i.e comparing organic molecules with the same number of carbons, such as ethane and ethanol, we can see that the boiling point of ethane is very much less than that of ethanol. This is due to the weak dispersion force holding ethane molecules together, as compared to the strong H-bonding holding ethanol molecules together.

Sodium iodide is an ionic compound, while sulfur hexafluoride is covalent. The ionic interplay is incredibly stable, and provides NaI extreme melting and boiling factors. The small ions additionally %. jointly effectively. SF6, on the different hand, has little intermolecular interplay, which ability the molecules separate somewhat effectively from one yet another. The molecules are additionally super and cumbersome, which ability they %. inefficiently. SF6 is likewise thoroughly symmetrical. The bonds are polar, however the dipoles cancel out thoroughly. This leaves the molecule devoid of internet everlasting dipole.

boiling point depends on polarity but also on molecular weight.... it depends on possibility of making Hydrogen bonds, it depends on what kind of molecule u have....e.g.: Diamond has a really higher boiling point then water.

ANyway in general it's not easy,but u have to specify what molecules u are considering...