1.
3. Arrange each series of compounds in order of decreasing rate of acid-catalyzed hydrolysis of
the corresponding diethyl acetals. Explain your reasoning.
a) acetaldehyde, chloroacetaldehyde, buten-2-al
b) acetaldehyde, formaldehyde, acetone
c) cyclopentanone, cyclohexanone, camphor
d) acetone, 3,3-dimethyl-2-butanone, 4,4-dimethyl-2-butanone
e) benzaldehyde, 4-methoxybenzaldehyde, butanal
Solution
a) but-2-enal > chloroacetaldehyde > acetaldehyde
b) acetaldehyde > acetone > formaldehyde.
c) camphor> cyclohexanone > cyclopentanone
d) 3,3 dimethyl -2- butanone > 4,4 dimethyl -2- butanone
e) 4-methoxybenzaldehyde > butanal . benzaldehyde.
KEEPING THE FOUR POINTS ABOVE SIMPLY WE CAN UNDERSTAND THE ORDER
OF EASE OF HYDROLYSIS, OTERWISE THE SUBJECT IS A GREAT RESEARCH
TREND PRESENTLY.
a) double bond attached to the carbon having aldehyde -CHO group., chlorine present in hte
compound which is having lone pair, acetaldehyde comes next with simple without any
substituents.SO RATE OF HYDROLYSIS AS GIVEN-- Â Â a) but-2-enal > chloroacetaldehyde
> acetaldehyde
b)formaldehyde is oxidisable , it is reducing agent. positive charge at c in aldehyde is more stable
than that in the ketone due to STERIC HINDRANCE prevaling on the carbonyl carbon in
acetone.
so,   acetaldehyde > acetone > formaldehyde.

2.
c) ring is strained in cyclopentanone and strain calle dtorsional strian increrases on the addition
of hydroxide ion at carbonyl carbon in cyclopentanone.cyclo hexane ring is balanced and
stabilised . camphor is favorable for hydrolysis more due to methyl group presece adjacent to the
carbony carbon
camphor> cyclohexanone > cyclopentanone
d)electron donating alkyl susubstituents present in two dimethyl compounds, the compound
which is having dimethyl group nearer to the carbonyl carbon is more stable than the other. so
order is
3,3 dimethyl -2- butanone > 4,4 dimethyl -2- butanone > acetone.( all are ketones , so stereic
hidrance case not to take into account)
e) aromatic ring is electron withdrawing so benzaldehyde is slow to hydrolysis, methoxy group is
electrondonating and so it is more stable than butanal.
oredr is  4-methoxybenzaldehyde > butanal .>benzaldehyde.
FIRST UNDERSTAND THE FOUR POINTS GIVEN IN HE BEGINNING
THEH KINETICS OF HYDROLYSIS OF CARBONYLS IS EXPLAINED WITH SIMPLE
BASICS HERE.