The considerably greater acidic strength of PhOH `(pK_(a) = 10) than that of ROH `(pK_(a) = 18)` is due to the fact that

Options

A. Pho- (phenoxide ion) is a stronger base than `RO^(-)`(alkoxide ion)
B. `PhO^(-)` (phenoxide ion) is weaker base than `RO^(-)`(alkoxide ion)
C. ROH is soluble in water
D. PhOH is aromatic in nature

Answer

B

Explanation

`underset("Phenol")(PhOH) hArr underset("Phenoxide ion")(Phoverset(-)O +H^(+))`
`underset("Alcohol")(R-OH) hArr underset("Alkoxide ion")(R - overset(-)O H^(+))`
Phenoxide ion is resonance stabileised, therefore it is weak base . While alkoxide ion is destabilised by the + l-effect of alkly group and hence , it is the stronger base . Agian , weaker the base , stronger is its conjugate acid. As phenoxide ion is weaker base , so phenol is the stronger acid than alcohol.