WAEC Chemistry Past Questions & Answers - Page 131

651.

Aluminium is extracted electrolysis from

A.

bauxite

B.

cryolite

C.

duralumin

D.

kaolin

Correct answer is A

No explanation has been provided for this answer.

652.

Which of the following processes does not involve the use of limestone?

A.

Extraction of iron in the blast furnance

B.

Manufacture of tetraoxosulphate (VI) acid by Contact process

C.

Production of washing soda by Solvay process

D.

Production of cement

Correct answer is B

No explanation has been provided for this answer.

653.

The following substances are ores of metals except

A.

bauxite

B.

cuprite

C.

cassiterite

D.

graphite

Correct answer is D

No explanation has been provided for this answer.

654.

The reagent that can be used to distinguish ethene from ethyne is

A.

ammoniacal silver trioxonitrate (V) solution

B.

Benedict solution

C.

bromine water

D.

Fehling's solution

Correct answer is A

To distinguish between ethene and ethyne: i Add a few drops of ammonical copper(I) chloride to each of ethylene (ethene) and acetylene (ethyne). No change will be observed in the case of ethylene (ethene) but in the case of acetylene (ethyne), a red precipitate of copper acetylide is formed. similar result

ii) When ammoniacal Silver Nitrate (AgNO3) is added to Ethyne then it gives white precipitates. But when Ammoniacal silver nitrate is added to Ethene then no reaction occurs and no precipitates obtain.

655.

The compound that makes palm wine taste sour after exposure to the air for few days is

A.

ethanol

B.

ethanoic acid

C.

methanol

D.

methanoic acid

Correct answer is A

No explanation has been provided for this answer.