JAMB Past Questions and Answers - Page 1569

7,841.

Which of the following does NOT happen when a zinc rod is introduced into a solution of copper (ll) sulphate?

A.

Electrons flow towards the zinc rod

B.

The zinc rod dissolves

C.

The temperature of the soil changes

D.

The blue colour of the solution gradually disappears

E.

Copper metal is deposited

Correct answer is A

No explanation has been provided for this answer.

7,842.

The chemical reaction which takes place at the anode (positive electrode) in electrolysis is?

A.

oxidation

B.

hydrolysis

C.

dissociation

D.

reduction

E.

disproportionation

Correct answer is A

No explanation has been provided for this answer.

7,843.

Which of the following silver halides is readily soluble in ammonium hydroxide?

A.

Agl

B.

AgBr

C.

AgCl

D.

AgF

E.

None of the above

Correct answer is C

No explanation has been provided for this answer.

7,844.

In which of the following is the oxidation state of oxygen different from its value in water?

A.

OH-

B.

H3O+

C.

O-

D.

H2O2

E.

SO2

Correct answer is D

No explanation has been provided for this answer.

7,845.

When dilute hydrochloric acid is added to iron(ll)sulphide, the gas evolved will?

A.

turn moist red litmus paper blue

B.

turn lime water milky

C.

blacken lead acetate paper

D.

rekindle a glowing splint

E.

burn a sqeakly pop

Correct answer is C

The gas liberated is H\(_2\)S which  in the presence of  lead acetate paper gives a black coloration