JAMB Chemistry Past Questions & Answers - Page 23

111.

On the basis of the electrochemical series, which of these ions will show the greater tendency to be discharged at the cathode in an electrolytic cell

A.

cu\(^{2+}\)

B.

sn\(^{2+}\)

C.

fe\(^{2+}\)

D.

zn\(^{2+}\)

Correct answer is A

The arrangement of elements in order of increasing electrode potential values is called electrochemical series.

K > Na > Ca > Mg > Al > Zn > Fe > Ni > Sn > Pb > H > Cu > Ag > Au.

112.

A chemical widely used as a fertilizer is?

A.

galena

B.

bauxite

C.

emerald

D.

nitrochalk

Correct answer is D

Calcium ammonium nitrate or CAN, also known as nitro-limestone or nitrochalk, is a widely used inorganic fertilizer.

113.

Addition of sodium chloride to water to form a solution would  lead to?

A.

increase in freezing point and increase the boiling point

B.

increase in freezing point and decrease the boiling point

C.

decrease in freezing point and decrease the boiling point

D.

decrease in freezing point and increase the boiling point

Correct answer is D

If you add salt to water, you lower its freezing point as well as raise its boiling point.

114.

An organic compound which liberate carbon(iv)oxide from trioxocarbonate(iv) solution is likely to be?

A.

C\(_2\)H\(_5\)OH

B.

C\(_3\)H\(_4\)

C.

C\(_6\)H\(_6\)

D.

CH\(_3\)COOH

Correct answer is D

Carboxylic acids and enols react with sodium bicarbonate to liberate carbon dioxide.

E,g CH\(_3\)COOH

115.

The sulphide that is commonly used in coating electric fluorescent tubes is?

A.

iron(ii)Sulphide

B.

tin(ii)sulphide

C.

Zinc Sulphide

D.

lead(iv) Sulphide

Correct answer is C

ZnS (Zinc Sulfide) screen was used because it emits a flash of light when struck by an alpha particle.

This is a phenomenon called Radio luminescence in which a flash of light is observed on the screen when acted upon by a radioactive substance.