JAMB Past Questions and Answers - Page 1621

8,101.

2SO2(g) + O2(g) → 2SO3. In the reaction above, the standard heats of formation of SO2(g) and SO3(g) are -297 KJ mol-1 and -396 kJ/mol respectively. The heat change of the reaction is?

A.

-99 kJ mol-

B.

-198 kJ mol-

C.

+198 kJ mol-

D.

+683kJ mol-

Correct answer is B

2SO2 + O2 → 2SO3
2(-297) 2(-396)
-594 -792
Heat change = heat of product - heat of reactants = -792 - (-594) = -198kj mol-

8,103.

What is the oxidation number of Z in K3ZCl6?

A.

-3

B.

+3

C.

-6

D.

+6

Correct answer is B

No explanation has been provided for this answer.

8,104.

How many Faraday of electricity are required to deposit 0.20 mole of nickel, if 0.10 Faraday of electricity deposited 2.98g of nickel during electrolysis of its aqueous solution?

(Ni = 58.7, 1F = 96 500 C mol-)

A.

0.20

B.

0.30

C.

0.40

D.

0.50

Correct answer is C

No of mole → (2.98)/(58.7) ..............0.1

2.0 .................x
∴ x = (0.2)/(2.98) x 58.7 x 0.40

8,105.

When platinum electrodes are used during the electrolysis of copper (ll) tetraoxosulphate (lV) solution, the solution gets progressively?

A.

acidic

B.

basic

C.

neutral

D.

amphoteric

Correct answer is A

No explanation has been provided for this answer.