Oxidation and reduction - Jamb Chemistry Past Questions and Answers

Question 41:

• JAMB 1990

Which of the following samples will react fastest with dilute trioxonitrate (V) acid?

A. 5 g of lumps of CacO₃ at 25°C
B. 5 g of powered CacO₃ at 25°
C. 5 g of lumps of CaCO₃ at 50°C
D. 5 g of powered CaCO₃ AT 50°C

Question 42:

• JAMB 1991

MnO^-₄ + 8H⁺ + ne → Mn⁺⁺ + 4H₂O. Which is the value of n in the reaction above?

A. 2
B. 3
C. 4
D. 5

Question 43:

• JAMB 1991

2H2S(g) + SO2(g) → 3S(s) + 2H2O(I). The above reaction is?

A. A redox reaction H₂S is the oxidant and SO₂ is the reductant
B. A redox reaction in which SO₂ is the oxidant and H₂S is the reductant
C. Not a redox reaction because there is no oxidant in reaction equation
D. Not a redox because there is no reductant in the reaction equation

Question 44:

• 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 45:

• 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