Oxidation and reduction - Jamb Chemistry Past Questions and Answers

Question 11:

• JAMB 1981

The oxidation number of manganese in KMnO₄ is?

A. +1
B. +3
C. +5
D. +7
E. +2

Question 12:

• JAMB 1981

Oxidation is the process of?

A. Gain of electrons
B. Loss of electrons
C. Gain of hydrogen
D. Loss of oxygen
E. Addition of an electropositive element to a substance

Question 13:

• JAMB 1981

In the reaction
C + 2HNO₃ → CO₂ + NO₂ + NO + H₂O nitric acid is acting as?

A. A reducing agent
B. A nitrating agent
C. An oxidizing agent
D. A catalytic agent
E. A neutralizing agent

Question 14:

• JAMB 1982

In the reaction NH3 + H+ → NH4+, the bond formed results from?

A. An electron transferred from NH₃ + H⁺
B. An electron pair donated by NH₃
C. An electron pair equally shared
D. An electron pair donated by H⁺
E. An electron tarnsferred from H⁺ to NH₃

Question 15:

• JAMB 1982

Which of the following equations represents an oxidizing action of sulphur dioxide?

A. SO₂ + 2HNO₂ → H₂SO₄ + 2NO₂ + heat
B. 2SO₂ + 2H₂O + O₂ → 2H₂SO₄
C. SO₂ + 2H₂O + CI₂ → H₂SO₄ + 2HCI
D. SO₂ + 2H₂S → 3S + 2H₂O
E. K₂Cr₂O₇ + H₂SO₄ + 3SO₂ → K₂SO₄ + Cr₂(SO₄)₃ + H₂O