Which one of the following compounds, is most acidic ?

Question

Which one of the following compounds, is most acidic ? (A)  Cl—CH2—CH2—OH  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

Phenols are much more acidic than alcohol due to the stabilisation of phenoxide ion resonance.

Phenoxide ion is stabilized due to following resonating structures:

While, in alcohols

Ortho nitrophenol is most acidic because in —NO2 electron attracting group is attached to ortho position which helps in stabilizing the negative charge on the oxygen of phenoxide ion. Hence, due to this reason acidic character of phenol is increased, while on attachment of —CH3 group (electron donating group) acidic strength of phenol is decreased in cresol due to the destabilization of phenoxide ion.

Q. Which one of the following compounds, is most acidic ?

$Cl — C H_{2} — C H_{2} — O H$

Q. Which one of the following compounds, is most acidic ?

Cl—CH2​—CH2​—OH

$Cl — C H_{2} — C H_{2} — O H$