Question

Why most of the alkanes are Hydrophobic in nature?

Answer 1

Because the `C-H` (and more so the `C-C`) bonds are relatively non-polar...

Explanation:

Water solubility, or if you like `"hydrophilicity"`, depends on the polarity of the bonds in the solute. Water can dissolve strongly polar materials which feature `OH` bonds. Water can also dissolve some ionic solutes, where polarity has graduated to complete charge separation.

On the other hand, `C-H` and `C-C` bonds are very non-polar, i.e. there is no charge separation that might be solvated by a polar solvent (such as water, or short chain alcohols). And thus the alkanes tend to have little solubility in aqueous media.