WAEC Chemistry Past Questions & Answers - Page 133

661.

Consider the following electrochemical cell notation: M(s) / M2+ (aq)// H+ (aq)/ H2(g). The value of the electrode potential is positive when?

A.

electrons flow from the metal electrode, M(s) to hydrogen electrode, H2(g)

B.

electrons fow from hydrogen electrode, H2(g) to metal electrode, M(s)

C.

the flow of current is high

D.

there is equilibrium between the flow of electrons from the hydrogen electrode, H2(g) to metal electrode, M(s)

Correct answer is B

No explanation has been provided for this answer.

662.

Which of the following metals could be used as sacrifical anode for preventing the corrosion of iron?

A.

Copper

B.

Lead

C.

Magnesium

D.

Silver

Correct answer is C

No explanation has been provided for this answer.

663.

What mass of copper would be formed when a current of 10.0 A is passed through a solution of CuSO4 for 1 hour? [Cu = 63.5; 1F = 96500C]

A.

5.9 g

B.

11.8 g

C.

23.8 g

D.

47.3 g

Correct answer is B

No explanation has been provided for this answer.

664.

What is the value of n in the following equation? Cr2O72- + 14H+ + ne- → 2Cr 3+ + 7H2O

A.

2

B.

3

C.

6

D.

7

Correct answer is C

No explanation has been provided for this answer.

665.

Consider the following reaction equation: X(g)
+ Y(g) ⇌ XY(g); ∆H = + 220KJ mol-1 If the temperature of the system is increased, the

A.

backward reaction would be favoured

B.

forward reaction would favoured

C.

reaction would stop

D.

reaction would be at equilibrium

Correct answer is B

No explanation has been provided for this answer.