Waec Chemistry 2002 Past Questions and Answers

Question 36:

• WAEC 2002

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

Question 37:

• WAEC 2002

Consider the following equation: Cr₂O^2-_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

Question 38:

• WAEC 2002

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^-

Question 39:

• WAEC 2002

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

Question 40:

• WAEC 2002

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