Halogenoalkanes and benzene

The molecules of halogenoalkanes are more polar than molecules of alkanes.

• True

• False

All C−halogen bonds are weaker than C−C and C−H bonds.

• True

• False

Answer explanation

C−F bond is a very strong bond (492 kJ mol⁻¹) and is much stronger than the C−C (346 kJ mol⁻¹) and C−H (414 kJ mol⁻¹) bonds

All the halogens are more electronegative than hydrogen and carbon.

• True

• False

Which reagents can react together to give 1-chlorobutane as a product ?

• but-2-ene and hydrogen chloride

• butane and chlorine in ultraviolet light

• but-1-ene and chlorine

• butane and hydrochloric acid

Which reactions produce butan-2-ol?

• warming 2-iodobutane with sodium hydroxide solution

• shining ultraviolet light on a mixture of butane and water

• heating but-2-ene with steam in the presence of an acid catalyst

Which is a secondary halogenoalkane?

• 2-iodobutane

• 1-chloropropane

• 2-chloro-2-methylpropane

• 1,2-dibromoethane

What will be the organic product from the reaction between warm dilute aqueous sodium hydroxide solution and 1-bromobutane?

• but-2-ene

• but-1-ene

• butan-1-ol

• butan-2-ol

Which reagent cannot act as a nucleophile?

• hydroxide ion

• water

• methane

• ammonia

Benzene, C₆H₆ can react with hydrogen at 180 ^oC in the presence of a nickel catalyst to form cyclohexane, C₆H₁₂.

• reduction

• hydrogenation

• addition

Benzene can react with chlorine in the presence of aluminium chloride to form chlorobenzene.

• reduction

• substitution

• chlorination