JAMB Chemistry Past Questions & Answers - Page 375

1,871.

When water boilers are used for long period of time, the solid substances left behind as scale are

A.

magnesium trioxosilicate (IV) and rust

B.

magnesium trioxosilicate (IV) and calcium tetraoxosulphate (VI)

C.

clay and magnesium troxosulphate (IV)

D.

clay and rust

Correct answer is A

No explanation has been provided for this answer.

1,872.

A substance that is used as a ripening agent for fruits is?

A.

ethene

B.

propene

C.

methane

D.

butane

Correct answer is A

- Ethene is a plant hormone which causes fruit to ripen.

- Ethene is used routinely within the food industry to provide controlled ripening during storage and transport or when fruit is displayed in shops, in sealed packages. 

1,873.

Equal moles of ethyne and hydrogen iodide react to give

A.

CH2 = CH2

B.

CH2 - CHI

C.

CH3 - CI

D.

CH2 = CHI

Correct answer is D

No explanation has been provided for this answer.

1,874.

How many hydrogen atoms does a single ring cycloalkane have less than the corresponding open-chain alkane?

A.

Two

B.

Three

C.

Four

D.

One

Correct answer is A

No explanation has been provided for this answer.

1,875.

In the purification of impure samples of ethyl ethanoate synthesized by esterification, concentrated sodium trioxocarbonate (IV) solution is used to remove

A.

water

B.

basic impurities

C.

acidic impurities

D.

ethoxyethane

Correct answer is C

No explanation has been provided for this answer.