WAEC Chemistry Past Questions & Answers - Page 41

201.

consider the reaction represented by the following equation: 2SO\(_2\) + O\(_2\)  ⇌ 2SO\(_3\) 

A decrease in the pressure of the reaction would

A.

decrease in the concentration of SO\(_2\)

B.

have no effect on the reaction

C.

shift the equilibrium position to the left

D.

shift the equilibrium position to the right

Correct answer is C

Decrease in pressure favors the side with higher volume thus the equilibrium position will shift to the left

202.

If the oxidation potential of Mg and Al are +2.37 volts and + 1.66 volts respectively, then the Mg would?

A.

not replace Al

B.

be replaced by Al

C.

remain in the solution

D.

replace Al

Correct answer is D

Cation which is lower in the series (less electropositive) will show a greater tendency to be discharged.

203.

The process by which alkanoic acid reacts reversibly with alkanols is known as?

A.

saponification

B.

esterification

C.

carboxylation

D.

halogenation

Correct answer is B

No explanation has been provided for this answer.

204.

The oxidation of chromium in Cr\(_2\)O\(_7)\(-2\) ?

A.

+4

B.

+5

C.

+6

D.

+7

Correct answer is C

2 atoms of Cr,

7 X -2 atoms of O

2Cr - 14 = -2

2Cr = -2 + 14

2Cr = 12

Cr = 6

205.

consider the following reaction equation: 2NH\(_3 \) .+ 3Cl\(_2\) → N2 + 6HCl. 

NH\(_3\) is acting as?

A.

a reducing agent

B.

a dehydrating agent

C.

a drying agent

D.

an oxidizing agent

Correct answer is A

- As a reducing agent, Ammonia reacts with chlorine to create nitrogen gas and hydrogen chloride vapour in the first step.