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1

NEET 2016 Phase 1

MCQ (Single Correct Answer)
The correct statement regarding a carbonyl compound with a hydrogen atom on its alpha-carbon, is
A
a carbonyl compound with a hydrogen atom on its alpha-carbon rapidly equilibrates with its corresponding enol and this process is known as carbonylation
B
a carbonyl compound with a hydrogen atom on its alpha-carbon rapidly equilibrates with its corresponding enol and this process is known as keto-enol tautomerism
C
a carbonyl compound with a hydrogen atom on its alpha-carbon never equilibrates with its corresponding enol
D
a carbonyl compound with a hydrogen atom on its alpha-carbon rapidly equilibrates with its corresponding enol and this process is known as aldehyde-ketone equilibration.

Explanation

Keto-enol tautomerism is as follows :
2

NEET 2016 Phase 1

MCQ (Single Correct Answer)
Which of the following reagents would distinguish cis-cyclopenta-1-2-diol from the trans-isomer?
A
MnO2
B
Aluminimum isopropoxide
C
Acetone
D
Ozone

Explanation



Trans isomer does not react with acetone as removal of H2O molecule is difficult.
3

AIPMT 2015

MCQ (Single Correct Answer)
Which one of the following esters gets hydrolysed most easily under alkaline conditions?
A
B
C
D

Explanation

Among the substituent attached to the benzene ring, –NO2 group is the most electron withdrawing, thus withdraws electron density from carbonyl carbon thus facilitate the attack of OH ion.
4

AIPMT 2015 Cancelled Paper

MCQ (Single Correct Answer)
An organic compound 'X' having molecular formula C5H10O yields phenylhydrazone and gives negative response to the iodoform test and Tollens' test. It produces n-pentane on reduction. 'X' could be
A
3-pentanone
B
n-amyl alcohol
C
pentanal
D
2-pentanone

Explanation

As the compound X yields phenyl hydrazone and gives negative response to the iodoform test and Tollen’s test so it must contain a C = O group but neither a methyl ketone nor in aldehyde. Thus, the structure of X will be

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