Chemistry 1997 Waec Past Questions and Answers

Question 16 :

• WAEC 1997

Which of the following ions will migrate to the cathode during electrolysis?

A. Zinc ions
B. Chloride ions
C. Sulphide ions
D. Tetraoxosulphate (Vl) ions
E. Trioxonitrate (V) ions

Question 17 :

• WAEC 1997

What quantity of electrons (in mole) is lost when one mole of iron (ll) ions is oxidized to iron (lll) ions?

A. 5 mole
B. 4 mole
C. 3 mole
D. 2 mole
E. 1 mole

Question 18 :

• WAEC 1997

The common feature of reactions at the anode is that

A. Electrons are consumed
B. Oxidation is involved
C. Ions are reduced
D. The electrode dissolves
E. The electrolyte is diluted

Question 19 :

• WAEC 1997

From the following equations, what is the order of decreasing reactivity of X, Y and Z? Y _(s) + X²⁺_(aq) → Y^{2+_(aq) + X_(s) X_(s) + Z[sup]2+}_(aq) → X²⁺_(aq) + Z_(s)[/sup]

A. X>Y>Z
B. Y > X > Z
C. Z > Y > X
D. Y > Z > X
E. X > Z > Y

Question 20 :

• WAEC 1997

What is the value of x in the following equation? MnO- ₄ + 4H⁺ + xe- → MnO ₂ + 2H₂O

A. 2
B. 3
C. 4
D. 7
E. 8