In: Chemistry
Arrange the following compounds in order of increasing acidity, and explain the reasons for your choice of order: cyclopentanol, phenol, p-nitrophenol, and 2- chlorocyclopentanol.
Acidity depends on the strenght of acid. Acid strength depends on its dissociation. Dissociation depends on the formation of stable conjugate base.
Stability of conjugate base depnds on the stability of negative charge formed. This is decided by two things, 1st is Resonance and second is inductive effect.
In case of two cyclohexanol and and -2cholorocycloepentanol there is no any resonance effect .
There are 6 resonance structures are possible for nitrophenol and so negative charge is delocalized more. so nitrophenol is strong acid then it is followed by nitrophenol which has 4 resonance structure. After that acidity is followed by cyclohexane and lowest acidity is of 2-chlorocyclopentanol becuase Cl is electron withdrawing groups which pulls electrond by inductive effect.
Lets show the structure , resonance and conjugate base.