Oxidation and reduction - Jamb Chemistry Past Questions and Answers

Question 21:

• JAMB 1984

In which of the following reactions does hydrogen peroxide act as a reducing agent?

A. H₂S + H₂O₂ \(\to\) S + 2H₂O
B. PbSO₃ + H₂O₂ \(\to\) PbSO₄ + H₂O
C. 2I+ 2H⁺ + H₂O₂ \(\to\) I₂ + 2H₂O
D. PbO₂ + 2HNO₃ + H₂O₂ \(\to\) Pb(NO₃)₂ + 2H₂O + O₂
E. SO₂ + H₂O₂ \(\to\) H₂SO₄

Question 22:

• JAMB 1984

For the reaction 2Fe³⁺ 2I^- \(\to\) 2Fe²⁺ + I₂, which of the following statements is TRUE?

A. Fe is oxidized to Fe³⁺
B. Fe³⁺ is oxidized to Fe²⁺
C. I^- is oxidized to I₂
D. I^- is reduced to I₂
E. I^- is displacing an electron from Fe³⁺

Question 23:

• JAMB 1984

3Cl₂ + 2NH₃ \(\to\) N₂ + 6HCl. In the above reaction, ammonia acts as

A. A reducing agent
B. An oxidizing agent
C. An acid
D. A catalyst
E. A dry agent

Question 24:

• JAMB 1984

In the Haber process for the manufacture of ammonia, finely divided iron is used as

A. An ionizing agent
B. A reducing agent
C. A catalyst
D. A dehydrating agent
E. An oxidizing agent

Question 25:

• JAMB 1984

Which of the following statements is INCORRECT?

A. Fractional distillation of crude petroleum will give the folloing hydrocarbon fuels in order of increasing boiling point
B. Butane < petrol < kerosene of polythene.
C. Both but-1-ene and but-1-yne will decolorize bromine readily
D. But-2-ene will react with chlorine to form 2,3-dichlorobutane
E. Calcuim carbide will react with water to form any alkyne