Question

How could we change methane (CHA) from a nonpolar molecule to a polar molecule? What could we substitute a hydrogen atom with

Answer 1

*Methane contains 4 C-H bonds. The electronegativity difference between C an H = 2.55-2.2 = 0.3

If the difference is less than 0.4 then the bond is non polar. If difference is greater than 0.4 then the bond is polar. Since all bonds in methane are non polar the molecule is non polar.

Now if we convert methane to methyl chloride then one polar C-Cl bond arises[in which the electro negativity difference between Cl and C is (3.15-2.55) = 0.6] which makes the molecule polar.Thus conversion of methane to methyl chloride makes the molecule polar.

CH4 --------------> CH3Cl +HCl , The reagent required is one equivalent Cl2 in presence of diffused sun Light .

**The H atom can be substituted by halogen atoms such as Cl, Br .