JAMB Past Questions and Answers - Page 1585

7,921.

20 cm3 of 1.0 molar NH4OH solution when neutralized with 20.05cm3 of 0.1 molar HCl liberated -102 joules of heat. Calculate the heat of neutralization of NH4OH?

A.

-51.O KJ mol-

B.

+57.3 KJ mol-

C.

+57.O KJ mol-

D.

+51.0 KJ mol-

Correct answer is A

NH4OH = 20cm of 0.1 m
NH4 + HCl → NH4Cl = H2O
Heat of Neutralization of NH4OH
= \(\frac{-102}{2}\) = -51.0 KJ mole-1

7,922.

Which of these represents a redox reaction?

A.

AgNO3 + NaCl → AgCAl + NaNO3

B.

H2S + Pb(NO3) → PbS + 2HNO3

C.

CaCO3 → CaO + CO2

D.

Zn + 2HCl → ZnCl2 + H2

Correct answer is D

No explanation has been provided for this answer.

7,923.

How many coulombs of electricity are passed through a solution in which 6.5 amperes are allowed to run for 1.0 hour?

A.

3.90 x 102 coulombs

B.

5.50 x 103 coulombs

C.

6.54 x 103 coulombs

D.

2.34 x 104 coulombs

Correct answer is D

No explanation has been provided for this answer.

7,924.

Which of the following solutions will conduct the least amount of electricity?

A.

2.00 M aqueous solution of NaOH

B.

0.01 M aqueous solution of NaOH

C.

0.01 M aqueous solution of hexanoic acid

D.

0.01 M aqueous solution of sugar

Correct answer is D

No explanation has been provided for this answer.

7,925.

Which of the following is an acidic salt?

A.

NaHSO4

B.

Na2SO4

C.

CH3CO2Na

D.

Na2S

Correct answer is A

A salt formed by the neutralisation of a strong acid and weak base is called acidic salt because its aqueous solution turns blue litmus red.