WAEC Chemistry Past Questions & Answers - Page 245

1,221.

Which of the following oxides is amphoteric?

A.

Na2O

B.

Fe2O3

C.

AI2O3

D.

CaO

E.

CuO

Correct answer is C

No explanation has been provided for this answer.

1,223.

The following salts dissolve readily in cold water except

A.

CaCI2

B.

PbSO4

C.

(NH4)2SO4

D.

Na2CO3

E.

Na2SO3

Correct answer is B

No explanation has been provided for this answer.

1,224.

Copper (ll) tetraoxosulphate (VI) is often added to swimming pools because it

A.

prevents the growth of algae

B.

coagulates suspended particles

C.

neutralizes dissolved gases in water

D.

reacts with any excess chlorine present

E.

increases the amount of dissolved oxygen

Correct answer is A

No explanation has been provided for this answer.

1,225.

Metals which react with steam only when they are red-hot include

A.

copper

B.

sodium

C.

calcium

D.

gold

E.

iron

Correct answer is E

No explanation has been provided for this answer.