Question

Why we cant make methane by wurtz reaction?

Answer 1

As per the Wurtz reaction method..
R-X + 2Na + XR ➡ R- R+ 2Na
here we will take any two alkyl halides... The two alkyl group combines together to form carbon chain more than C2H6... just think in logical way... any two least alkyl halides combines to form carbon chain from C2H6- CnHn
Ex: CH3 I + 2Na+ ICH3➡C2H6 + 2NaI

Answer 2

Wurtz reaction is suitable for symmetrical alkane at product side with same kind of alkyl halide (primary and secondary alkyl halide only) at reactant side(because if different alkyl halide are taken then mixture of different alkane are formed which is difficult to separate). So from this reaction there will be formation of alkane with at least one C-C bond.But methane has no any such bond(i.e. has only C-H bond). R-X + 2Na + X-R → R-R + 2NaX in presence of dry ether.

Hence methane cannot be prepared from Wurtz reaction.