JAMB Chemistry Past Questions & Answers - Page 328

1,636.

Which of the following salts is slightly soluble in water?

A.

AgCl

B.

CaSO4

C.

Na2CO3

D.

PbCl2

Correct answer is B

All sulfates are soluble except those of barium, strontium and lead. Calcium sulfate, silver sulfate and mercurous sulfate are slightly soluble in water, but calcium sulfate is rarely precipitated in reactions between the calcium and sulfate ions.

1,637.

The colour of methyl orange in alkaline medium is?

A.

yellow

B.

pink

C.

orange

D.

red

Correct answer is A

Methyl orange has the property to color alkaline and neutral water yellow.

1,638.

Calculate the volume of 0.5 mol dm-3 H2So4 that is neutralized by 25 cm3 of 0.1 mol dm-3 NaOH?

A.

5.0 cm3

B.

2.5 cm3

C.

0.4 cm3

D.

0.1 cm3

Correct answer is B

No explanation has been provided for this answer.

1,639.

The acid that is used to remove rust is?

A.

boric

B.

hydrochloric

C.

trioxonitrate (V)

D.

tetraoxosulphate (VI)

Correct answer is B

No explanation has been provided for this answer.

1,640.

Carbon (II) oxide is considered dangerous if inhaled mainly because it?

A.

can cause injury to the nervous system

B.

competes with oxygen in the blood

C.

competes with carbon (IV) oxide in the blood

D.

can cause lung cancer

Correct answer is B

Carbon monoxide is harmful when breathed because it displaces oxygen in the blood and deprives the heart, brain and other vital organs of oxygen.