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For the following half-reactions, answer the questions below: $$ \begin{array}{cc} \mathrm{Ce}^{4+}(a q)+e^{-} \longrightarrow \mathrm{Ce}^{3+}(a q) & E^{\circ}=+1.61 \mathrm{~V} \\ \mathrm{Ag}^{+}(a q)+e^{-} \longrightarrow \mathrm{Ag}(s) & E^{\circ}=+0.80 \mathrm{~V} \\ \mathrm{Hg}_{2}^{2+}(a q)+2 e^{-} \longrightarrow 2 \mathrm{Hg}(l) & E^{\circ}=+0.80 \mathrm{~V} \\ \mathrm{Sn}^{2+}(a q)+2 e^{-} \longrightarrow \mathrm{Sn}(s) & E^{\circ}=-0.14 \mathrm{~V} \\ \mathrm{Ni}^{2+}(a q)+2 e^{-} \longrightarrow \mathrm{Ni}(s) & E^{\circ}=-0.24 \mathrm{~V} \\ \mathrm{Al}^{3+}(a q)+3 e^{-} \longrightarrow \mathrm{Al}(s) & E^{o}=-1.68 \mathrm{~V} \end{array} $$ (a) Which is the weakest oxidizing agent? (b) Which is the strongest oxidizing agent? (c) Which is the strongest reducing agent? (d) Which is the weakest reducing agent? (e) Will \(\mathrm{Sn}(s)\) reduce \(\mathrm{Ag}^{+}(\mathrm{aq})\) to \(\mathrm{Ag}(s) ?\) (f) Will \(\mathrm{Hg}(l)\) reduce \(\mathrm{Sn}^{2+}(a q)\) to \(\mathrm{Sn}(s) ?\) (g) Which ion(s) can be reduced by \(\operatorname{Sn}(s)\) ? (h) Which metal(s) can be oxidized by \(\mathrm{Ag}^{+}(a q)\) ?

Short Answer

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Answer: Al鲁鈦

Step by step solution

01

Find the weakest oxidizing agent

An oxidizing agent is a species that gains electrons and causes the oxidation of another species. The weakest oxidizing agents are the least likely to gain electrons or have the lowest reduction potential. In our case, the species with the lowest reduction potential is Al鲁鈦 with a value of -1.68 V. Therefore, Al鲁鈦 is the weakest oxidizing agent. The answer to (a) is Al鲁鈦.
02

Find the strongest oxidizing agent

The strongest oxidizing agents are the most likely to gain electrons or have the highest reduction potential. In our case, the species with the highest reduction potential is Ce鈦粹伜 with a value of +1.61 V. Therefore, Ce鈦粹伜 is the strongest oxidizing agent. The answer to (b) is Ce鈦粹伜.
03

Find the strongest reducing agent

A reducing agent is a species that loses electrons and causes the reduction of another species. The most powerful reducing agents have the lowest reduction potential in their reverse redox reactions. In our case, the reverse reaction of Al鲁鈦, which is the oxidation of Al(s), has the lowest reduction potential. Thus, Al(s) is the strongest reducing agent. The answer to (c) is Al(s).
04

Find the weakest reducing agent

The weakest reducing agents have the highest reduction potential in their reverse redox reactions. In our case, the reverse reaction of Ce鈦粹伜, which is the oxidation of Ce鲁鈦, has the highest reduction potential. Thus, Ce鲁鈦 is the weakest reducing agent. The answer to (d) is Ce鲁鈦.
05

Test if Sn(s) will reduce Ag鈦(aq) to Ag(s)

To determine if Sn(s) will reduce Ag鈦(aq) to Ag(s), we need to consider their reduction potentials. If the reduction potential of Sn虏鈦/Sn is lower than Ag鈦/Ag, Sn(s) will act as a reducing agent and reduce Ag鈦(aq) to Ag(s). Sn虏鈦/Sn has a reduction potential of -0.14 V, while Ag鈦/Ag has one of 0.80 V. Since the reduction potential of Sn虏鈦/Sn is lower, Sn(s) will reduce Ag鈦(aq) to Ag(s). The answer to (e) is yes.
06

Test if Hg(l) will reduce Sn虏鈦(aq) to Sn(s)

The same logic applies to determine if Hg(l) will reduce Sn虏鈦(aq) to Sn(s). If the reduction potential of Hg虏虏鈦/Hg is lower than Sn虏鈦/Sn, Hg(l) will act as a reducing agent and reduce Sn虏鈦(aq) to Sn(s). Hg虏虏鈦/Hg has a reduction potential of 0.80 V, while Sn虏鈦/Sn has one of -0.14 V. Since the reduction potential of Hg虏虏鈦/Hg is not lower, Hg(l) will not reduce Sn虏鈦(aq) to Sn(s). The answer to (f) is no.
07

Find which ions can be reduced by Sn(s)

Sn(s) can reduce ions with higher reduction potentials than Sn虏鈦/Sn. Comparing Sn虏鈦/Sn (-0.14 V) with the given species, we find that Sn(s) can reduce Ce鈦粹伜(aq) (1.61 V), Ag鈦(aq) (0.80 V), and Hg虏虏鈦(aq) (0.80 V). The answer to (g) is Ce鈦粹伜, Ag鈦, and Hg虏虏鈦.
08

Find which metals can be oxidized by Ag鈦(aq)

Ag鈦(aq) can oxidize metals with lower reduction potentials than Ag鈦/Ag. Comparing Ag鈦/Ag (0.80 V) with the given species, we find that Ag鈦(aq) can oxidize Sn(s) (-0.14 V), Ni(s) (-0.24 V), and Al(s) (-1.68 V). The answer to (h) is Sn, Ni, and Al.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Oxidizing Agent
In the realm of redox reactions, an oxidizing agent is the substance that breathes life into the process by gaining electrons. Imagine it as a character in our chemical story that takes electrons away from another, thereby causing that other substance to lose electrons, a process we call oxidation. The strength of an oxidizing agent is best understood through its appetite for electrons, measured by something called the standard reduction potential. A high positive value indicates a strong desire to gain electrons and hence a stronger oxidizing power. For example, in our textbook problem, Ce4+ with its generous +1.61 V of standard reduction potential is the strongest oxidizing agent, very eager to snag electrons and get reduced to Ce3+.

On the other hand, Al3+, bearing a less enthusiastic -1.68 V, is seen as the least desirous of electrons, making it our weakest oxidizing agent. This measure helps us predict which substances will be more likely to drive the redox reaction forward by acting as the electron-hungry entity.
Reducing Agent
Reducing agents, the electron donors in the chemistry dance, do the opposite of their oxidizing partners: they give away electrons to others. This generosity allows them to reduce others while they themselves become oxidized. Their strength is inversely related to that of the corresponding oxidized form in the electrochemical series, with a lower or more negative standard reduction potential indicating a mightier reducing prowess. In our exercise, Al(s) is heralded as the strongest reducing agent 鈥 it has the lowest potential when its reaction is flipped (-1.68 V), showing a distinct readiness to let go of its electrons.

Ce3+, with the highest (though still negative) potential in its reverse reaction, is considered the weakest reducing agent. This helps us to compare different substances and their abilities to push a redox reaction by surrendering electrons.
Standard Reduction Potential
The standard reduction potential (E掳) is a numerical value that indicates just how willing a substance is to be reduced. In other words, it tells us how much a substance would like to gain electrons. Measured in volts (V), these values serve as a sort of 'chemical currency' for the electron exchange rate in redox reactions. The higher the positive value, the greater the substance's desire to adopt electrons and be reduced, functioning as an oxidizing agent. Conversely, a lower or negative value indicates a stronger tendency to donate electrons, characteristic of reducing agents.

This concept is crucial for predicting the direction of redox reactions and for solving exercises like ours. For example, the question about whether Sn(s) can reduce Ag+ is answered by comparing their potential: Sn(s), at -0.14 V, can reduce Ag+, which has a higher potential of +0.80 V.
Electrochemical Series
The electrochemical series is essentially a leaderboard of substances ranked by their standard reduction potential. It's a powerful tool for students to predict the outcome of redox reactions. Substances at the top with higher E掳 values are strong oxidizing agents, eager to gain electrons. Those at the bottom, with lower or negative E掳 values, are strong reducing agents, ready to donate electrons.

Let's apply this to our textbook problem. With the electrochemical series, we can easily deduce that Al(s), sitting at lower ranks due to its -1.68 V potential, can be oxidized by just about any substance higher up in the series, such as Ag+ with its +0.80 V. Conversely, Ce4+ (+1.61 V) reigns over most others with its high rank, asserting it can reduce many substances below it in the series. This ranking serves as an invaluable cheat sheet for determining the likelihood of various redox reactions occurring.

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Most popular questions from this chapter

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