Explanation

(b)
(a) Shows tautomerism since aldehydes are more stable than vinyl alcohols
$C_{6}H_{5} - CH = CHOH\ \leftrightarrow C_{6}H_{5}CH_{2} - CH_{2} - CH_{2} = 0$
(b) Does not show tautomerism because it does not have hydrogens at $\alpha$-positions
( c ) Shows tautomerism because enol form is stabilized by H-bonding
[image:9_image158.emf]
(d) Shows tautomerism because enol form is stabilized by aromatic character
[image:9_image159.emf]