JAMB Chemistry Past Questions & Answers - Page 279

1,391.

In an electrolytic set-up to protect iron from corrosion, the iron is?

A.

made cathode

B.

made anode

C.

used with a metal of lower electropositive potential

D.

initially coated with tin

Correct answer is A

In cathodic protection,iron object is made cathode by connecting it with reactive elements like magnesium,zinc.

1,392.

SO3 is NOT directly dissolved in water in the preparation of H2SO4 by the contact process because?

A.

the reaction between SO3 and water is violently exothermic

B.

acid is usually added to water and never water to acid

C.

SO3 does not dissolve in water readily

D.

SO3 is an acid gas

Correct answer is A

No explanation has been provided for this answer.

1,393.

Which of these solutions will give a white precipitate with a solution of barium chloride acidified with hydrochloric acid?

A.

Sodium trioxocarbonate (IV)

B.

Sodium tetraoxosulphate (IV)

C.

Sodium trioxosulphate (IV)

D.

Sodium sulphide

Correct answer is B

The characteristic test for any soluble tetraoxosulphate(VI) is the formation of white precipitate (barium sulphate) when a solution of barium chloride, acidified with dilute HCl, or when a solution of barium nitrate, acidified with dilute nitric acid is reacted with it.

1,394.

Clothes should be properly rinsed with water after bleaching because?

A.

the bleach decolourizes the cothes

B.

chlorine reacts with fabrics during bleaching

C.

the clothes are sterilized during bleaching

D.

hydrogen chloride solution is produced during bleaching

Correct answer is D

No explanation has been provided for this answer.

1,395.

Which of these metals CANNOT replace hydrogen from alkaline solutions?

A.

Alulinium

B.

Zinc

C.

Tin

D.

Iron

Correct answer is D

No explanation has been provided for this answer.