[INeedSerotonin]

Hello

Could you please teach me how to solve this (non-balanced) equation?

2-Bromo-3,4-dimethylpentane + Na ------> NaBr + X

What is "x"?

Answer: 2,3,4,5,6,7-hexamethyl-octane

I have seen some resolution saying that we should use two moles of the alkane and of sodium, but I'm still totally lost here. I know this is the Wurtz synthesis.

Shouldn't this become a decane with four methyl groups? How on Earth can this become an octane ?!?!?!? 

Thanks!

[AWK]

It is just dimerization.

[Enthalpy]

Because bromine is on position 2. The new link isn't at the ends of the bromo- reactant but between the former positions 2. So you get a hexamethyloctane rather than a tetramethyldecane.