1

### AIPMT 2011 Prelims

Which one is a nucleophilic substitution reaction among the following ?
A
B
C
D

## Explanation

Because of high electronegativities of the halogen atom, the carbon halogen (C – X) is highly polarised covalent bond. Thus, the carbon atom of the C – X bond becomes a good site for attack by nucleophiles (electron rich species). Nucleophilic substitution reactions are the most common reactions of alkyl halides.
2

### AIPMT 2011 Prelims

Which one of the following is most reactive towards electrophilic reagent?
A
B
C
D

## Explanation

+R effect of -OH group is greater than of -OCH3 group. That is why it is highly reactive towards electrophilic substitutions.
3

### AIPMT 2011 Prelims

The correct IUPAC name for the compound is

A
4-ethyl-3-propylhex-1-ene
B
3-ethyl-4-ethenylheptane
C
3-ethyl-4-propylhex-5-ene
D
3-(1 -ethylpropyl)hex- 1 -ene.

## Explanation

4-ethyl-3-propylhex-1-ene
4

### AIPMT 2011 Prelims

Considering the state of hybridization of carbon atoms, find out the molecule among the following which is linear ?
A
CH3 $-$ CH $=$ CH $-$ CH3
B
CH3 $-$ C$\equiv$C $-$ CH3
C
CH2 $=$ CH $-$ CH2 $-$ C$\equiv$CH
D
CH3 $-$ CH2 $-$ CH2 $-$ CH3

## Explanation

The carbon atoms which have sp hybridization form a linear molecule. Among the given compounds, has sp hybridized carbon atoms which has bond angle 180o are attached to sp3 hybridised carbon atoms. So, it is linear.