JAMB Chemistry Past Questions & Answers - Page 410

2,046.

In which of the following reactions has the oxidation number of nitrogen increased?

A.

2NO(g) + Br2(l) → 2NOBr(l)

B.

2NO(g) + O2(g) → 2NO2(g)

C.

FeSO4(aq) + NO(g) → Fe(NO)SO4(s)

D.

2NO(g) + Cl2(g) → 2NOCl(l)

Correct answer is B

No explanation has been provided for this answer.

2,047.

As the concentration of an electrolyte reduces, the conductivity

A.

reduces to zero

B.

decreases

C.

increase

D.

is unaffected

Correct answer is C

No explanation has been provided for this answer.

2,048.

When ΔH is negative, a reaction is said to be

A.

ionic

B.

reversible

C.

exothermic

D.

endothermic

Correct answer is C

No explanation has been provided for this answer.

2,049.

3Cu(s) + 8HNO3(aq) 3Cu(NO3)2(aq) + 4H2O(l) + 2NO(g)
In the equation above, copper is

A.

an electron acceptor

B.

a base

C.

an oxidizing agent

D.

a reducing agent

Correct answer is D

A reducing agent (also called a reductant or reducer) is an element or compound that loses (or "donates") an electron to another chemical species in a redox chemical reaction. Since the reducing agent is losing electrons, it is said to have been oxidized. In the reaction, Copper is oxidized.

2,050.

2SO2(g) + O2(g) ↔ 2SO3(g)
ΔH = -189 kJ mol-1
The equilibrium constant for the reaction above is increased by?

A.

decreasing the temperature of the system

B.

Increase the pressure of the system

C.

The addition of a catalyst to the system

D.

Increasing the surface area of the vessel

Correct answer is A

Decrease in temperature favors in Equilibrium Constant[k] for this exothermic reaction.