Rotation around carbon-carbon single bond of ethane is not completely free. Justify the statement.

2

(a)

On converting benzene to toluene, state whether there will be a rise or fall in the melting point.

2

(a)

Why do you alkenes prefer to undergo electrophilic addition reaction while arenes prefer electrophilic substitution reactions? Explain.

2

(a)

Draw the cis and trans structures of hex-2-ene. Which isomer will have higher b.p. and why?

2

(a)

What effect does branching of an alkane chain has on its boiling point?

2

(a)

Suggest the name of another Lewis acid instead of anhydrous aluminium chloride which can be used during ethylation of benzene.

2

(a)

What are shapes of
(i) CH₂ = CH₂
(ii) HC\(\equiv \)CH

2

(a)

What are conformations?

2

(a)

Why are alkanes called paraffins?

2

(a)

Arrange the three isomers of pentane in increasing order of their boiling points.

2

(a)

Which is more acidic: ethene or ethyne and why?

2

(a)

What is Huckel rule?

2

(a)

What happens when benzene is treated with acetyl chloride in presence of AlCl₃?

2

(a)

What are Arenes?

2

(a)

Write the structure of the alkene which on reductive ozonolysis gives butanone and ethanol.

2

(a)