WAEC Past Questions and Answers - Page 1753

8,761.

The following compounds contain the same type of bonds except

A.

sodium chloride

B.

hydrogen chloride

C.

magnesium chloride

D.

potassium chloride

E.

lithium chloride

Correct answer is B

No explanation has been provided for this answer.

8,762.

When magnesium ribbon burns in air, the products are

A.

magnesium nitride and magnesium oxide

B.

magnesium nitride and carbon (ll) oxide

C.

magnesium oxide and steam

D.

magnesium nitride and soot

E.

magnesium oxide and carbon (ll) oxide

Correct answer is C

No explanation has been provided for this answer.

8,763.

Destructive distillation of coal means

A.

heating coal in plentiful supply of air

B.

burning coal in air to produce water and carbon (IV) oxide

C.

heating coal in the absence of air

D.

heating coal in limited supply of air

E.

separating coal into various allotropes of carbon

Correct answer is C

No explanation has been provided for this answer.

8,764.

Study the reaction represented by the equation: Alkanol + Alkanoic acid conc. H2SO4 Alkanoate + water. The type of process involved in the reverse reaction is

A.

Neutralization

B.

dehydration

C.

hydrolysis

D.

decomposition

E.

hydrogenation

Correct answer is C

No explanation has been provided for this answer.

8,765.

Which of the following is likely to have the highest degree of hardness?

A.

Carbonated water

B.

Distilled water

C.

Acidified water

D.

Rain water

E.

Lime water

Correct answer is E

Hardness in water is mainly due to the presence of dissolved minerals such as calcium and magnesium ions, carbonated water, and rainwater with added carbon dioxide either naturally or artificially do not contain a great amount of these dissolved minerals hence they are less likely to have a high degree of hardness compared to lime water which contains calcium ions from the dissolved calcium hydroxide.