(1)
alcohols fails to turn blue litmus red while phenol do so.
(2) alcohols
fails to neutralize alkalies whereas phenols do so:
(3) Both
phenol and phenoxide ions exhibit resonance, whereas alcohols and alkoxide ion
do not.
(4) Due
to resonance, positive charge 's developed over "O"of phenol, this
weakens O-H bond and facilitates release of a proton. On the other hand. due to
electron donating nature of alkyl group. -O-H bond is strengthened. therefore.
it hinders the release of proton.
(5) The
phenoxide ion is more stable than phenol, due to o greater dispersal of
negative charge, therefore. equilibrium get shifted to forward direction.
whereas alkoxide ion is less stable than alcohols due to intensification of
negative charge, so equilibrium get shifted towards backward direcrion. Due
to these fact it is clear that phenols are more acidic than alcohols.
Related Questions:
(1) Benzamide
is less easily hydrolysed than methyl benzoate. Why ?
(2) Highly
branched carboxylic acids are less acidic than unbranched acids. Explain why?
(3) Phenoxide ion is more stable than an alkaoxide. why?
(4) What
is Steric Inhibition of Deprotonation effect ? Or SID effect ?
(6) Why
is o-toluic acid (2-methyl benzoic acid) stronger than benzoic acid ?
(7) Which
is more acidic 2-methyl benzoic acid , 3-methyl benzoic acid or 4-methyl
benzoic acid.?
