JAMB Chemistry Past Questions & Answers - Page 332

1,656.

Organic molecules that have the suffix-ene are unsaturated hydrocarbons that have?

A.

a single bond

B.

a double bond

C.

a triple bond

D.

an ionic bond

Correct answer is B

In chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.

1,657.

The simplest branched-chain hydrocarbon is

A.

ethane

B.

ethene

C.

propane

D.

butane

Correct answer is D

The smallest branched alkane is isobutane. Notice that isobutane has the same molecular formula, C4H10, as n-butane but has a different structural formula.

1,658.

The molecular formula of a common organic laboratory anaesthetic is

A.

CHCl3

B.

CHI3

C.

CCl4

D.

CHF3

Correct answer is A

No explanation has been provided for this answer.

1,659.

Which of the following hydrocarbons is mainly used as fuel?

A.

Methylene

B.

Ethylene

C.

Methane

D.

Ethyne

Correct answer is C

No explanation has been provided for this answer.

1,660.

An organic compound reacted with bromine water to give a colourless solution. The compound is probably an?

A.

alkene

B.

alkanal

C.

alkyl

D.

alkanone

Correct answer is A

Alkenes react in the cold with pure liquid bromine, or with a solution of bromine in an organic solvent like tetrachloromethane. The double bond breaks, and a bromine atom becomes attached to each carbon. The bromine loses its original red-brown colour to give a colourless liquid.

Alkynes also react with bromine, decolorising it though not as immediate as alkenes.