Redox Reactions

Consider the following reaction.

NO₃⁻ (aq) + Cu (s) → NO (g) + Cu²⁺ (aq)

Which statement is correct?

• Cu (s) is the reducing agent because it loses electrons.

• Cu (s) is the reducing agent because it gains electrons.

• Cu (s) is the oxidizing agent because it loses electrons.

• Cu (s) is the oxidizing agent because it gains electrons.

Al (s) + FeSO₄ (aq) → Al₂(SO₄)₃ (aq) + Fe (s)

Which statements are true about this reaction?

I. It is a disproportionation reaction.

II. It is a single displacement reaction.

III. It is an oxidation-reduction reaction.

• I and II only

• I and III only

• II and III only

• I, II and III

Given the following activity series: Zn > Fe > H₂ > Cu

Which statement is NOT true?

• Zinc is the strongest reducing agent among the three metals

• Zinc is the strongest oxidizing agent among the three metals

• Iron ions can be reduced by zinc

• Copper ions can be reduced by iron

When Cl₂ and KBr react, the leftmost mixture is obtained. The other three vials are control setups with aqueous Cl₂, Br₂ and I₂ mixed with toluene respectively. Which statement is TRUE?

• Cl₂ reduces Br^- to Br₂.

• Cl₂ oxidizes Br^- to Br₂.

• There is no reaction.

• The product cannot be determined.

What is the oxidation number of Mn in the following: MnO₄^-, MnO₄^2- and MnO₂?

• +4, +6, +7

• +7, +6, +4

• +2, +4, +7

• +5, +3, +4

What is the oxidizing agent in the following reaction?

Zn (s) + Cu²⁺ (aq) → Zn²⁺ (aq) + Cu (s)

• Zn (s)

• Cu²⁺ (aq)

• Zn²⁺ (aq)

• Cu (s)

What is the reducing agent in the following reaction?

• MnO₄^-

• SO₃^2-

• H⁺

• Mn²⁺

Al (s) + FeSO₄ (aq) → Al₂(SO₄)₃ (aq) + Fe (s)

Which statements are true about this reaction?

I. Al (s) reduces Fe²⁺ (aq)

II. Al (s) is the oxidizing agent.

III. FeSO₄ is the reducing agent.

• I and II only

• I and III only

• II and III only

• I, II and III

A student performed redox reactions using metals W and X and solutions of W²⁺, X²⁺, Y²⁺ and Z²⁺. The results are summarized in the table.

Which of the four metals is the strongest reducing agent?

• W

• X

• Y

• Z

Which statement is NOT true when the following redox reaction is balanced?

Cu (s) + NO₃^- (aq) → NO (g) + Cu²⁺ (aq) [acidic]

• There are 8H+ (aq) in the reactant side.

• There are 2H₂O (l) in the product side.

• There are 4H₂O (l) in the product side.

• There are 6e- in both half-equations.