JAMB Chemistry Past Questions & Answers - Page 356

1,776.

Dissolving some pellets of NaOH in water would result in

A.

a decrease in the free energy of the solution

B.

a decrease in the entropy of the solution

C.

a lowering of the temperature of te solution

D.

an increase in the entropy of the solution

Correct answer is D

No explanation has been provided for this answer.

1,777.

The salt formed from strong acid and a strong base is?

A.

complex

B.

neutral

C.

basic

D.

acidic

Correct answer is B

Sodium chloride, which is obtained by neutralization of hydrochloric acid and sodium hydroxide, is a neutral salt.

Neutralization of any strong acid with a strong base always gives a neutral salt.

1,778.

Tartaric acid is used industrially to

A.

make baking powder

B.

make fruit juices

C.

remove rust

D.

dry substance

Correct answer is A

No explanation has been provided for this answer.

1,779.

How long would it take to deposit 0.08g of copper from CuCl2 solution by passing a current of 0.5A?
[Cu = 64, F = 96500 C mol-1]

A.

6 mins

B.

8 mins

C.

24 mins

D.

48 mins

Correct answer is B

Cu2+ + 2e → Cu(s)
2 * 96500C deposit 64g of Cu
x quantity of electricity wil deposit 0.08
x = (2 * 96500 * 0.08)/64 =241.25 coulomb.
Q = It
241.25 = 0.5t
t = 241.25/60 = 8 mins

1,780.

C2H4(g) + H2(g) → C2H6(g) ΔH = -137kJ mol-1
The reaction represented above is

A.

exothermic

B.

spontaneous

C.

endothermic

D.

in equilibrium

Correct answer is A

No explanation has been provided for this answer.