WAEC Past Questions and Answers - Page 1757

8,781.

Glucose can be obtained from starch by

A.

hydrogenation

B.

dissoiation

C.

hydrolysis

D.

dialysis

E.

dehydration

Correct answer is C

No explanation has been provided for this answer.

8,782.

If the volume of a given mass of gas at 0oC is 27.3cm3, what will be the volume of the gas at 10oC, pressure remaining constant?

A.

2.73cm3

B.

28.3cm3

C.

37.3cm3

D.

273cm3

E.

283cm3

Correct answer is B

No explanation has been provided for this answer.

8,783.

Which of the following occurs when an aqueous solution of sodium hydroxide is electrolysed using graphite electrodes?

A.

Sodium metal is produced at the anode

B.

Sodium amalgam is formed at the cathode

C.

Oxygen gas is produced at the anode

D.

The grahite anode dissolves

E.

The resulting solution becomes acidic

Correct answer is C

No explanation has been provided for this answer.

8,784.

When naphthalene on heating changes from the solid state directly to the gaseous state it undergoes

A.

evaporation

B.

sublimation

C.

decomposition

D.

combustion

E.

ionisation

Correct answer is B

No explanation has been provided for this answer.

8,785.

Calcium is usually extracted by the electrolysis of its

A.

trioxonitrate (V)

B.

tetraoxosulphate (IV)

C.

oxide

D.

hydride

E.

chloride

Correct answer is E

No explanation has been provided for this answer.