Deciding the major product in this Wurtz reaction Today I was told:


  When 2-chlorobutane is reacted with 2-chloropropane in the presence of sodium and dry ether the following products are formed: 



2,3-dimethylpentane
3,4-dimethylhexane
2,3-dimethylbutane



  3,4-dimethylhexane, being most symmetric, is the major product.


I'm not satisfied with the reason provided. Can anyone please explain the fact in a better manner?



What I'm unable to understand is that both 3,4-dimethylhexane and 2,3-dimethylbutane and equally symmetric since both have a plane of symmetry, don't they? Then how are we using symmetry to compare the yield?
I think that there should be a 'statistical product distribution', if I'm correct the products should be in the ratios 2:1:1.

You get to this conclusion as follows, call 2-chlorobutane A and 2-chloropropane B.

A can react with A to give AA, and
A can react with B to give AB, while
B can react with A to give BA, while
B can react with B to give BB.

When you realise that AB and BA are the same molecule you get AA:2AB:BB; that is, 1:2:1.