Arrange water, ethanol and phenol in increasing order of acidity and give reason for your answer.
Arrange water, ethanol and phenol in increasing order of acidity and give reason for your answer.
The phenoxide ion obtained after the removal of a proton is resonance stabilized as follows
Whereas, the ethoxide ion obtained after the removal of. a proton is not stabilized but destabilized due to + I effect of - C2H5 group. Therefore, phenol is a stronger acid than ethanol.
Now, ethanol is a weaker acid than water because the electron releasing ethyl group increases the ethanol density on oxygen and consequently the proton will not be released easily. + I effect of CH3−CH2 group increase the electron density on O - H bond in ethanol. The electron density on the O - H bond of ethanol is more than that of water. There is no such effect is water.
Thus, the increasing order of acidity is ethanol < water < phenol.
The phenoxide ion obtained after the removal of a proton is resonance stabilized as follows
Whereas, the ethoxide ion obtained after the removal of. a proton is not stabilized but destabilized due to + I effect of - C2H5 group. Therefore, phenol is a stronger acid than ethanol.
Now, ethanol is a weaker acid than water because the electron releasing ethyl group increases the ethanol density on oxygen and consequently the proton will not be released easily. + I effect of CH3−CH2 group increase the electron density on O - H bond in ethanol. The electron density on the O - H bond of ethanol is more than that of water. There is no such effect is water.
Thus, the increasing order of acidity is ethanol < water < phenol.
