1

AIPMT 2005

Names of some compounds are given. Which one is not in IUPAC system?
A
B
C
D

Explanation

2

AIPMT 2005

The chirality of the compound
A
R
B
S
C
E
D
Z

Explanation

3

AIPMT 2005

Which amongst the following is the most stable carbocation?
A
$\mathop C\limits^ +$H3
B
CH3$\mathop C\limits^ +$H2
C
D

Explanation

3o C is more stable due to the stabilization of the charge by three methyl groups (or inductive effect). It can also be explained on the basis of hyperconjugation.
4

AIPMT 2005

Which of the following undergoes nucleophilic substitution exclusively by SN1 mechanism?
A
Ethyl chloride
B
Isopropyl chloride
C
Chlorobenzene
D
Benzyl chloride

Explanation

SN1 reaction is favoured by heavy groups on the carbon atom attached to halogen i.e

Benzyl > allyl > tertiary > primary > secondary > primary > alkyl halides