WAEC Chemistry Past Questions & Answers - Page 170

846.

A solution of a salt X reacts with AgNO3 solution to give white precipitate which dissolves in excess aqueous ammonia. X contains

A.

CI-

B.

Pb 2+

C.

SO 2-

D.

Zn2+

Correct answer is A

No explanation has been provided for this answer.

847.

What process is illustrated below? S(s) ⇌H2O⇌ S (aq)

A.

Decomposition of a solid

B.

Melting of a solid

C.

Formation of saturated solution of a solid

D.

Sublimation of a solid

Correct answer is C

From the  given equation:
\(S_{(s)} ⇌ S_{(aq)}\) (in the presence of (\(H_2O\))
The solid form has changed to an aqueous solution upon dissolution in water. Due to the presence of the reversible reaction arrow ⇌, the solution (aqueous) formed is saturated, this is because a saturated solution is an equilibrium system

848.

Which of the following compounds is a basic salt?

A.

Mg(NO3)2

B.

(NH4)2SO4

C.

K4Fe(CN)6

D.

Zn(OH)CI

Correct answer is D

No explanation has been provided for this answer.

849.

Consider the reaction represented by the equation: Ca(OH)2(aq) + CO 2(g) → CaCO3(s) + H 2O(l)
in the reaction above, CO 2 acts as

A.

an acidic oxide

B.

an oxidizing agent

C.

a basic oxide

D.

a dehydrating agent

Correct answer is A

No explanation has been provided for this answer.

850.

In which of the following compound (s) will heat be absorbed on adding water?

l. KNO\(_3\) II. Concentrated H\(_2\)SO\(_4\) III. NH\(_4\)CI

A.

I only

B.

lll only

C.

l and lll only

D.

ll and lll only

Correct answer is C

KNO\(_3\) and NH\(_4\)Cl both undergo endothermic.