WAEC Chemistry Past Questions & Answers - Page 98

486.

When concentrated sodium chloride solution is electrolysed using inert electrodes, the products are

A.

oxygen and hydrogen

B.

hydrogen and chlorine

C.

sodium and oxygen

D.

sodium and chlorine

Correct answer is B

No explanation has been provided for this answer.

487.

If two metallic ions of the same concentration migrate to a graphite cathode, the one that would be preferentially discharged is the one that has the

A.

smaller mass

B.

lower electrical charge

C.

greater stability in solution

D.

stronger tendency to accept electrons

Correct answer is D

No explanation has been provided for this answer.

488.

Which of the following ions require the largest quantity of electricity for discharge at an electrode?

A.

2.0 mole of Q 3+

B.

2.5 mole of R2+

C.

3.0 mole of T-

D.

4.0 mole of Y-

Correct answer is A

No explanation has been provided for this answer.

489.

Consider the following equation: Cr2O2-7(aq) + 14H+(aq) + 6e- → 2Cr3+(ag) + 7H2O(1). The oxidation number of chromium changes from

A.

-2 to + 3

B.

-2 to + 6

C.

+6 to +3

D.

+7 to + 6

Correct answer is C

No explanation has been provided for this answer.

490.

A visible change is observed when a strip of iron is placed in an aqueous solution of

A.

FeSO4

B.

ZnSO4

C.

CuSO4

D.

MgSO4

Correct answer is C

No explanation has been provided for this answer.