JAMB Chemistry Past Questions & Answers - Page 318

1,586.

In the reaction:
2Hl(g) ↔ H2(g) + l2(g)' ΔH = 10 kj;

The concentration of iodine in the equilibrium mixture can be increased by?

A.

raising the pressure

B.

raising the temperature

C.

adding a catalyst

D.

lowering the pressure

Correct answer is B

No explanation has been provided for this answer.

1,587.

Which of the following samples will react fastest with dilute trioxonitrate (V) acid?

A.

5 g of lumps of CacO3 at 25°C

B.

5 g of powered CacO3 at 25°

C.

5 g of lumps of CaCO3 at 50°C

D.

5 g of powered CaCO3 AT 50°C

Correct answer is D

No explanation has been provided for this answer.

1,588.

Iron galvanized with zinc is cathodically protected from corrosion. This is because?

A.

zinc has a more positive oxidation potential than iron

B.

zinc has less positive oxidation potential than iron

C.

bith have the same oxidation potential

D.

zinc is harder than iron

Correct answer is A

Iron galvanized with zinc is cathodically protected from corrosion because Zinc has a more positive oxidation potential than iron. This means that Zinc will preferentially corrode, acting as a sacrificial anode.

1,590.

In the reaction 1O-3 + 5l- + 6H+ → 312 + 3H2O, the oxidizing agent is?

A.

H+

B.

l-

C.

1O-

D.

l2

Correct answer is C

No explanation has been provided for this answer.