1

### AIPMT 2005

The best method for the separation of naphthalene and benzoic acid from their mixture is
A
distillation
B
sublimation
C
chromatography
D
crystallisation.

## Explanation

Sublimation would be the best method because it is applicable for those organic compounds which pass directly from solid to vapour state on heating and vice versa on cooling. In these compounds naphthalene is volatile and benzoic acid is nonvolatile due to the formation of dimer via intermolecular hydrogen bonding.
2

### AIPMT 2005

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

## Explanation

3

### AIPMT 2005

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

## Explanation

4

### 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.