Question

What is the pH of butane?

Answer 1

Butyl-lithium is a very common laboratory reagent. The `pK_a` of the parent acid, i.e. butane, has been estimated at `50`.

Explanation:

Of course we must specify the solvent when we discuss acid base chemistry. In water, hydroxide ion is the strongest base.

But other solvent systems exist. Butyl-lithium is supplied as a hexanes solution. It deprotonates just about everything (of course you have to take steps to remove trace water).

Answer 2

It doesn't have one.

Explanation:

pH is a measure of the acidity or basicity of an aqueous solution, being the negative of the base 10 logarithm of the molar concentration of hydroxonium (`H_3O^+`) ions that are formed when the solution is created.

However, butane does not dissociate in water, and therefore does not form any hydroxonium ions. Therefore the concept of pH does not apply to it..