WAEC Chemistry Past Questions & Answers - Page 239

1,191.

What is the role of MnO2 in the reaction represented by the following equation?MnO2 + 4HCI2 + CI2 + 2H2O

A.

Bleaching agent

B.

Oxidizing agent

C.

Amphoteric oxide

D.

Basic oxide

E.

Catalyst

Correct answer is B

No explanation has been provided for this answer.

1,192.

The cleansing action of soap in hard water is not satisfactory because soap

A.

forms insoluble calcium and magnesium salts

B.

is made from fats and oils

C.

has an organic component

D.

alters the surface tension of water

E.

is a sodium salt of higher carboxylic acids

Correct answer is A

No explanation has been provided for this answer.

1,193.

During water treatment for town supply, water is passed through layers of send beds in order to

A.

soften the water

B.

filter the water

C.

decolorize the water

D.

destroy the germs in the water

E.

coagulate colloidal particles in the water

Correct answer is B

No explanation has been provided for this answer.

1,194.

The component of air that can be removed by alkaline pyrogallol solution is

A.

oxygen

B.

nitrogen

C.

water vapour

D.

carbon (IV) oxide

E.

noble gases

Correct answer is A

No explanation has been provided for this answer.