JAMB Chemistry Past Questions & Answers - Page 285

1,421.

A pure solid usually melts?

A.

over a wide range of temperature

B.

over a narrow range of temperature

C.

at a lower temperature than the impure one

D.

at the same temperature as the impure one

Correct answer is B

No explanation has been provided for this answer.

1,422.

A mixture of sand, ammonium chloride and sodium chloride is best separated by?

A.

sublimation followed by addition of water and filteration

B.

sublimation followed by addition of water and evaporation

C.

addition of water followed by filtration and sublimation

D.

addition of water followed by crystallization and sublimation

Correct answer is A

No explanation has been provided for this answer.

1,423.

The confirmatory test for alkanoic acids in organic qualitative analysis is the?

A.

turning of wet blue litmus paper red

B.

reaction with alkanols to form esters

C.

reaction with sodium hydroxide to form salt and water

D.

reaction with aqueous Na2COsp3 to liberate a gas which turns lime water milky

Correct answer is B

No explanation has been provided for this answer.

1,424.

Which of the following represents saponification?

A.

Reaction of carboxylic acids with sodium hydroxide

B.

Reaction of alkanoates with acid

C.

Reaction of alkanoates with alcohols

D.

Reaction of alkanoates with sodium hydroxide

Correct answer is D

No explanation has been provided for this answer.

1,425.

Catalytic hydrogenation of benzene produces?

A.

an aromatic hydrocarbon

B.

margarine

C.

cyclohexane

D.

D.D.T

Correct answer is C

No explanation has been provided for this answer.