JAMB Chemistry Past Questions & Answers - Page 256

1,276.

A common characteristic shared by iron and aluminium is that both?

A.

are extracted by reduction methods

B.

form only basic oxides

C.

show oxidation states of +2 and +3

D.

form soluble hydroxides

Correct answer is A

No explanation has been provided for this answer.

1,277.

The metal that will react with water only in the form of steam to librate hydrogen gas is?

A.

calcium

B.

aluminium

C.

iron

D.

zinc

Correct answer is C

No explanation has been provided for this answer.

1,278.

Which of the following is observed when a solution of iron (III) chloride is mixed with a solution of sodium hydroxide?

A.

A gas is evolved

B.

A deep blue precipitate is formed

C.

The resultant solution turns green turns

D.

A brown precipitate is formed

Correct answer is D

Iron(III) chloride is a yellow solution
sodium hydroxide is colourless
iron(III) hydroxide is a reddish brown precipitate
sodium chloride is colourless

So in the reaction, yellow solution when added to sodium hydroxide forms reddish brown precipitate that is insoluble in excess sodium hydroxide.

1,279.

The oxide that remains unchanged when heated in hydrogen is?

A.

CuO

B.

Fe2O3

C.

PbO2

D.

ZnO

Correct answer is D

Zinc oxide doesn't react to hydrogen gas because the reaction is not spontaneous.

1,280.

A solution containing chloride ions gives white precipitate with silver trioxonitrate(V) Solution. The precipitate will be insoluble in dilute?

A.

HNO 3 but soluble in ammonia solution

B.

HNO3 and ammonia solution

C.

HCl but soluble in ammonia solution

D.

HCl and in ammonia solution

Correct answer is A

No explanation has been provided for this answer.