JAMB Chemistry Past Questions & Answers - Page 115

571.

Which of the following statements best explains cracking ? It is a process

A.

in which an alkene adds on itself repeatedly to form long chain polymers

B.

in which large hydrocarbon molecules are broken into smaller units

C.

for measuring theoctane number of petrol

D.

in which carbon chain results in a zigzag arrangement

E.

in which aromatic hydrocarbons are produced

Correct answer is B

No explanation has been provided for this answer.

572.

The major raw material in a plastic industry is

A.

ethanol

B.

sulphur

C.

methylethanoate

D.

ethene

E.

ethane

Correct answer is D

- Earlier, molasses act as a raw material which yield ethanol from which ETHENE (gotten is used to) produce a range of poly(ethene) plastics.

- Nowadays, starting new raw materials are obtained by the fractional distillation of crude oil or petroleum.

- During the thermal cracking of petroleum; long chain alkanes are converted into smaller chain alkanes, ALKENES (with Ethene being the predominate), etc.

- The Alkenes such as Ethene and Propene can be made into Poly(ethene) / plastic, nylon, etc.

575.

The complex salt formed when aluminium dissolves in sodium hydroxide solution is

A.

Na3AI(OH)4

B.

Na2AI(OH)3

C.

NaAI(OH)3

D.

Na4AI(OH)4

E.

NaAI(OH)4

Correct answer is E

No explanation has been provided for this answer.