Chemistry 1992 Jamb Past Questions and Answers

Question 21 :

• JAMB 1992

Copper (II) tetraoxosulphate (VI) solution is electrolyzed using carbon electrodes. Which of the following are produced at the anode and cathode respectively ?

A. Copper and oxygen
B. Oxygen and copper
C. Hydrogen and copper
D. Copper and hydrogen

Question 22 :

• JAMB 1992

Calculate the mass, in kilograms, of magnesium produced by the electrolysis of magnesium (II) chloride in a cell operating for 24 hours at 500 amperes.

A. 2.7
B. 5.4
C. 10.8
D. 21.7

Question 23 :

• JAMB 1992

S₂O^2-₃ + I₂ → S₂O₆^2- + 2I^-. In reaction above, the oxidizing agent is?

A. S₂O₃^2-
B. I₂
C. S₄O₆^2-
D. I^-

Question 24 :

• JAMB 1992

MnO₂ + 2CI^- + 4H⁺ → MnO²⁺ + CI₂ + 2H₂O.
The changes is oxidation numbers when the manganese, chloride and hydrogen ions react according to the above equation are respectively?

A. 2, 2, 4
B. -1, -2, 4
C. -2, 1, 0
D. 2, 4, 0

Question 25 :

• JAMB 1992

In which of the following is the entropy change positive?

A. H₂O_(I) → H₂O_(g)
B. Cu²⁺_{(aq) + Fe[sub](s)} → Fe⁽²⁺⁾ + Cu_(s)[/sub]
C. N_2(g) + 3H_2(g) → 2NH_3(g)
D. 2HCI_(s) → H_2(g) + CI_2(g)