1

### AIPMT 2010 Prelims

In the following the most stable conformation of n-butane is
A
B
C
D

## Explanation

The anti-conformation is the most stable conformation of n-butane. In this, the bulky methyl groups are as far apart as possible thereby keeping steric repulsion at a minimum.
2

### AIPMT 2010 Prelims

Liquid hydrocarbons can be converted to a mixture of gaseous hydrocarbons by
A
oxidation
B
cracking
C
distillation under reduced pressure
D
hydrolysis

## Explanation

On cracking or pyrolysis, the hydrocarbon with higher molecular mass gives a mixture of hydrocarbons having lower molecular masses. Hence, liquid hydrocarbons can be converted into a mixture of gaseous hydrocarbons. (Lower hydrocarbons exist in gaseous state while higher ones are in liquid state or solid state.)
3

### AIPMT 2009

The state of hybridisation of C2, C3, C5 and C6 of the hydrocarbon,

is in the following sequence
A
sp3, sp2, sp2 and sp
B
sp, sp2, sp2 and sp3
C
sp, sp2, sp3 and sp2
D
sp, sp3, sp2 and sp3

## Explanation

$\therefore$ C2 - sp, C3 - sp3, C5 - sp2 and C6 - sp3
4

### AIPMT 2009

Which of the following compounds will exhibit cis-trans (geometrical) isomerism?
A
Butanol
B
2-Butyne
C
2-Butenol
D
2-Butene

## Explanation

Alkenes with double bonds cannot undergo free rotation and can have different geometrical shapes with two different groups on each end of the double bond.