WAEC Chemistry Past Questions & Answers - Page 262

1,306.

Chlorine is is used in water treatment as

A.

a germicide

B.

a decolorizing agent

C.

an antioxidant

D.

a coagulating agent

E.

an aerating agent

Correct answer is A

No explanation has been provided for this answer.

1,307.

In which of the following changes is ∆S negative ?

A.

H2O(l) → H2O(s)

B.

C(s) + 1/2O2,/sub>(g) → CO(g)

C.

PCI5(g) → PCl3(g) + Cl2(g)

D.

NaCl(s) + aq →Na+ (aq) + Cl- (aq)

E.

NH3(g) + HCl(g)

Correct answer is A

No explanation has been provided for this answer.

1,308.

Sulphur burns in air to form

A.

an acidic oxide

B.

a basic oxide

C.

an amphoteric oxide

D.

a neutra oxide

E.

a mixed oxide

Correct answer is A

No explanation has been provided for this answer.

1,309.

What does X atand for in the following expression? X = Log(10)(H+)

A.

Enthalpy change (∆H)

B.

Equilibrium constant (K)

C.

Solubility product

D.

Degree of acidity (pH)

E.

lonic product of water

Correct answer is D

No explanation has been provided for this answer.

1,310.

Carbon is often deposited in the exhaust-pipe of cars because of the?

A.

presence of carbon in petrol

B.

presence of carbon in petrol

C.

incomplete combustion of petrol

D.

presence of additives in petrol

E.

contamination of petrol with diesel

Correct answer is C

The incomplete combustion process that occurs in an engine; result to the emission of carbon monoxide (CO) as a waste product from the exhaust system of vehicles.

Environmental carbon monoxide is produced by incomplete combustion process from any carbon containing fuel.