JAMB Chemistry Past Questions & Answers - Page 24

116.

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. 

117.

How many neutrons are present in atom with mass number and atomic number 37 and 17 respectively?

A.

18

B.

20

C.

37

D.

17

Correct answer is B

The mass number = number of neutrons + atomic number.

number of neutrons = The mass number - atomic number.

number of neutrons = 37 - 17 = 20

118.

The following non-metal form acidic oxides with oxygen except?

A.

phosphorus

B.

sulphur

C.

carbon

D.

chlorine

Correct answer is C

The oxides which neither react with acids nor react with bases are known as neutral oxides. 

Carbon monoxide neither reacts with acids nor reacts with bases.

Thus, carbon monoxide is a neutral oxide, produced when combustion reactions are not fully completed, either through lack of oxygen or due to low mixing

119.

In the preparation of salts, the method employed will depend on the?

A.

composition

B.

dissociating ability

C.

stability to heat

D.

precipitating ability

Correct answer is C

The method used to prepare a salt depend on:

the solubility of the salt in water.

the heat stability of the salt

120.

SO\(_2\) + O\(_2\) → 2SO\(_3\)

In the reaction above, the most suitable catalyst is?

A.

chromium(vi)oxide

B.

iron(iii)oxide

C.

copper(i)oxide

D.

vanadium(v)oxide

Correct answer is D

During the Contact Process for manufacturing sulfuric acid, sulfur dioxide has to be converted into sulfur trioxide, which is done by passing sulfur dioxide and oxygen over a solid vanadium(V) oxide catalyst.