Question

How would you convert ethyl bromide to butane?

Answer 1

You might do it via an acetylene synthesis.

The `"NaH"` acts like a hydride (`"H":^(-)`) Lewis base to take off the proton from the acetylene, and then the acetylide can act as a nucleophile to attack the ethyl bromide. That gives you a four-carbon hydrocarbon.

pKa of acetylene: `25`
pKa of `"H"_2`: `35`

Now just reduce it with hydrogen gas catalyzed by palladium over carbon for full reduction (not stopping at the alkene).