11.1.4 The Activity Series of the Elements

Question 1

The Activity Series of the Elements

Answer 1

• The spontaneity of a redox reaction depends on the relative redox strengths of the component species.
• There is an inverse relationship between the strength of a metal as a reductant and its cation as an oxidant; a metal that is a strong reductant will have a cation that is a weaker oxidant.
• The redox activity series relates the relative redox strengths of elements.

Question 2

note

Answer 2

• When copper wire is placed into a solution of silver nitrate (AgNO 3 ), a redox reaction occurs resulting in a solution of copper nitrate Cu(NO 3 ) 2 and silver metal (Ag 0 ). In this reaction Cu is oxidized (donates electrons) and Ag + is reduced (gains electrons). The reducing agent is Cu, while the oxidizing agent is Ag + .
• The spontaneity of this redox reaction depends on the relative redox strengths of the component species.
• If a silver spoon is placed into the solution the reverse reaction will not occur. Copper metal is a better reducing agent than silver metal (it is able to lose electrons more easily), thus silver metal cannot react with Cu(NO 3 ) 2 to reform Cu 0 and AgNO 3 .
• There is an inverse relationship between the strength of a metal as a reductant and its cation as an oxidant; a metal that is a strong reductant will have a cation that is a weak oxidant.
• If a strip of zinc metal were placed in a solution of copper nitrate Cu(NO 3 ) 2 what would happen? The answer depends on which is the better reducing agent, copper metal or zinc metal (which is able to donate electrons more easily?).
• The redox activity series reveals relative redox strengths of elements.
• The chart shows that copper cation is a better oxidizing agent (oxidant) than zinc cation, therefore, copper cation is more easily reduced than zinc cation. This means that Cu(NO 3 ) 2 would react with Zn 0 to form Cu 0 and Zn(NO 3 ) 2 .

Question 3

Look again at the redox activity series.

Which statement about this series is not correct?

Answer 3

The list gives you accurate, immediate information on the capability of Zn2+ to act as a reducing agent.

Question 4

Which statement about an oxidant and its corresponding reducing agent is correct?
Example: In the reaction
K+ (aq) + e− → K(s)
K+ is the oxidant and K(s) is its corresponding reducing agent.

Answer 4

A strong oxidant will have a weak corresponding reducing agent.

Question 5

When silver nitrate and copper wire interact, a spontaneous reaction occurs.

Cu(s) + 2Ag(NO3 ) (aq) → Cu(NO3 )2(aq) + 2Ag(s)

Which of the following explains why this reaction occur spontaneously?

Answer 5

• Silver is a better oxidizing agent than copper.
• Silver is a weaker reducing agent than copper.
• Copper is a better reducing agent than silver.

Question 6

When a copper wire is placed in silver nitrate solution:

Cu(s) + 2Ag(NO3 ) (aq) → Cu(NO3 )2(aq) + 2Ag(s)

The final solution is blue in color. In addition, a metallic powder precipitates. Which of the following correctly summarizes this event?

Answer 6

Ag(NO3 ) (aq) is the oxidant. Cu(s) is the reducing agent. Cu(NO3 )2(aq) is the final solution. Ag(s) is the metallic powder.

Question 7

Assume that that following reactions is part of the activity series as listed

M1n+ (aq) + ne− → M1
M2n+ (aq) + ne− → M2

Which of the following is correct?

Answer 7

The spontaneous reaction is M1 + M2n+ → M2 + M1n+

Question 8

This list of reduction reactions is a helpful tool for predicting how two metals and metal ions will interact with one another. Which statement about the redox activity series is not correct?

Answer 8

As you move down the list, the ability of the metal component to reduce another metal increases.

Question 9

Which of the following correctly shows what happens in the two half-reaction steps (oxidation and reduction) in a redox reaction?

Answer 9

In oxidation reactions, there is a loss of electrons. As a result, there is an increase in the oxidation number. Conversely, in reduction reactions, there is a gain of electrons. As a result, there is a decrease in the oxidation number.

Question 10

This list of reduction reactions is a helpful tool for predicting how two metals will interact with one another. Suppose that we are looking for a metal to react in a specific manner with magnesium. Which of the following correctly describes and lists the metal that will achieve our desired goal?

Answer 10

We want a metal that will cause magnesium ion(Mg2+ ) to be reduced spontaneously. We choose calcium metal.

Question 11

We learned that iron pipes can form rust very easily. In the initial reaction, iron metal interacts with O2 and H + to form an iron cation and water.

Fe(s) + ½O2(g) + 2H + (aq) → Fe2+ (aq) + H2O

Which statement about this phenomenon is not correct?

Answer 11

This is not a redox reaction.

Question 12

In an expanded redox activity series, aluminum is located above iron. Which statement correctly predicts what will happen (or not happen) when these two metals and its cations interact?

Answer 12

Aluminum will act as the stronger reducing agent and iron metal ion will act as the stronger oxidant.