Question

Which of the following alcohol is the weakest acid in water?

• A. Ethyl alcohol
• B. Phenol
• C. Methyl alcohol
• D. t- Butyl alcohol

Answer 1

The correct option is D t- Butyl alcohol

$t-Butyl$ alcohol is the weakest acid in water.

The order of reactivity is:

$Phenol>Methyl$ $alcohol>Ethyl$ $alcohol>t-butyl$ $alcohol$.

In phenol, phenoxide ion is very stable. This is due to the partial delocalization of the negative charge on the oxygen over the benzene ring.

$P_{ka}$ Value $Phenol\left(9.95\right)>Methyl$ $alcohol\left(15.5\right)>Ethyl$ $alcohol\left(15.9\right)>t-butyl$ $alcohol\left(16.5\right)$.