Processing math: 100%

JAMB Chemistry Past Questions & Answers - Page 153

761.

The colour of litmus in a neutral medium is

A.

purple

B.

pink

C.

yellow

D.

orange

Correct answer is A

The colour of a neutral litmus solution is purple.

Litmus solution is made up of purple dye which is extracted from Lichens.

It is a natural Indicator and it is used to indicate the presence of an acid or a base.

A litmus paper will turn red in the presence of an acid and it turns blue in the presence of a base.

762.

The basicity of CH<sub>3</sub>COOH is

A.

4

B.

1

C.

2

D.

3

Correct answer is B

No explanation has been provided for this answer.

763.

The major and most effective way of controlling pollution is to

A.

improve machinery so that the substances released from combustion are less harmful

B.

pass strict laws against it by individuals and companies

C.

educate people on the causes and effects of pollution

D.

convert chemical wastes to harmless substances before releasing them into the environment

Correct answer is C

No explanation has been provided for this answer.

764.

The dispersion of a liquid in a liquid medium will give

A.

an emulsion

B.

a fog

C.

a gel

D.

an aerosol

Correct answer is A

No explanation has been provided for this answer.

765.

16.55g of lead (ll) trioxonitrate (V) was dissolved in 100g of distilled water at 20oC, calculate the solubility of the solute in moldm-3

[Pb = 207, N = 14, O = 16]

A.

0.05 g

B.

2.00 g

C.

1.00 g

D.

0.50g

Correct answer is D

molar mass of pb (N0 3) 2 = 331
Mole = 16.55331= 0.05 mole
∴0.05mole pb (No3)2 dissolved in 1000g H2O x = 0.05×1000100= 0.5 mole /dm 3