WAEC Chemistry Past Questions & Answers - Page 132

656.

When bromine is added to ethene at room temperature, the compound formed is

A.

1,1 - dibromoethane

B.

1,2 - dibromoethene

C.

1,1 - dibromoethene

D.

1,2 - dibromoethane

Correct answer is D

Ethene is an alkene, meaning it has a carbon to carbon double bond. When Bromine is added, an addition reaction occurs forming 1,2 dibromoethane.

C2H4 + Br2 -> C2H4Br2

657.

The following substances are examples of addition polymer except

A.

nylon

B.

perspex

C.

polyethene

D.

polychloroethene

Correct answer is A

Every option, except nylon (which is a condensation polymer), is an addition polymer.

658.

Which of the following separation techniques would show that black ink is a mixture of chemical compounds?

A.

Crystallization

B.

Chromatography

C.

Filtration

D.

Sublimation

Correct answer is B

No explanation has been provided for this answer.

659.

Which of the following compounds would react with ethanoic acid to give a sweet smelling liquid?

A.

Alkane

B.

Alkanol

C.

Alkanal

D.

Alkyne

Correct answer is B

No explanation has been provided for this answer.

660.

Which of the following compounds determines the octane rating of petrol?

A.

1,2,3 - trimethlpentane

B.

2,3,5 - trimethyloctane

C.

2,3,5 - trimethylpentane

D.

2,2,4 - trimethylpentane

Correct answer is D

No explanation has been provided for this answer.