15 Multiple Choice Questions on Redox Reactions

Oxidation is defined as:

• Gain of electrons

• Loss of electrons

• Gain of oxygen

• Loss of hydrogen

Reduction is defined as:

• Gain of electrons

• Loss of electrons

• Gain of oxygen

• Loss of hydrogen

The substance that loses electrons in a redox reaction is called the:

• Oxidizing agent

• Reducing agent

• Catalyst

• Inert substance

The substance that gains electrons in a redox reaction is called the:

• Oxidizing agent

• Reducing agent

• Catalyst

• Inert substance

In the reaction Zn + CuSO₄ → ZnSO₄ + Cu, which species is oxidized?

• Zn

• Cu

• SO₄²⁻

• No oxidation occurs

The oxidation number of oxygen in most compounds is:

• +2

• -2

• 0

• +1

The oxidation number of an element in its elemental form is:

• +1

• -1

• 0

• Depends on the element

In the reaction 2Fe³⁺ + 2I⁻ → 2Fe²⁺ + I₂, the oxidation number of iron changes from:

• +3 to +2

• +2 to +3

• -2 to 0

• 0 to -2

Balancing redox reactions involves:

• Balancing mass only

• Balancing charge only

• Balancing both mass and charge

• None of the above

The half-reaction method is used to balance redox reactions by:

• Balancing oxidation and reduction half-reactions separately

• Directly balancing the overall equation

• Using oxidation numbers only

• Trial and error