Standard reduction electrode potentials of three metals A, B and C are +0.5 V, -3.0 V and -1.2 V, re

Q: Why does a negative reduction potential mean high reducing power?

A negative reduction potential indicates that the substance does not want to gain electrons; instead, it prefers to lose them (oxidation). Since reducing agents work by losing electrons to other substances, a higher tendency to lose electrons means a stronger reducing power.

Q: What if the question gave oxidation potentials instead?

Oxidation potential is simply the negative of the reduction potential ($E^\circ_{\text{ox}} = -E^\circ_{\text{red}}$). A higher positive oxidation potential means a higher tendency to get oxidized, which directly translates to a higher reducing power.

Q: Can a metal with a positive reduction potential act as a reducing agent?

Yes, but it will be a very weak reducing agent. It can only reduce substances that have an even higher positive reduction potential than itself.

Q: How do we remember the trend in the electrochemical series?

Think of Lithium at the top (most negative $E^\circ$, strongest reducing agent) and Fluorine at the bottom (most positive $E^\circ$, strongest oxidizing agent). Metals generally have negative potentials and act as reducing agents.

Q: Is reducing power the same as the chemical reactivity of metals?

For metals, yes! The reactivity of a metal is its ability to lose electrons to form positive ions. Therefore, highly reactive metals like Sodium or Potassium are also exceptionally strong reducing agents with highly negative reduction potentials.

Question

Standard reduction electrode potentials of three metals $A, B$ and $C$ are $+0.5	ext{ V}, -3.0	ext{ V}$ and $-1.2	ext{ V}$, respectively. The reducing power of these metals are

Options:

(A) $B > C > A$

(B) $A > B > C$

(C) $C > B > A$

(D) $A > C > B$

Sigma Percentile · Accepted Answer

### Decoding the Electrochemical Series

Imagine a grand tug-of-war, but instead of a rope, the teams are fighting over **electrons**. This is the essence of electrochemistry! Every element has a certain desire to pull electrons towards itself, and we measure this desire using the **Standard Reduction Potential ($E^\circ$)**.

When an element has a high, positive $E^\circ$, it is screaming, "Give me electrons!" It wants to be reduced. On the flip side, an element with a highly negative $E^\circ$ is saying, "Take my electrons, I don't want them!"

### The Power to Reduce

Now, let's talk about **reducing power**. A reducing agent is a chemical species that reduces another substance. But to do this noble deed, it must sacrifice its own electrons—it must undergo **oxidation**.

Therefore, the best reducing agents are the ones that lose electrons the easiest. And who loses electrons the easiest? The elements with the most negative standard reduction potentials!

Mathematically, we can state this golden rule:
$$ 	ext{Reducing Power} \propto \frac{1}{E^\circ_{	ext{reduction}}} $$

The more negative the $E^\circ$ value, the stronger the reducing power.

### Analyzing the Contenders

In our problem, we have three metallic gladiators:
*   **Metal A:** $E^\circ = +0.5	ext{ V}$
*   **Metal B:** $E^\circ = -3.0	ext{ V}$
*   **Metal C:** $E^\circ = -1.2	ext{ V}$

Let's rank them based on their eagerness to give away electrons (their reducing power).

**Metal B** has a massively negative potential of $-3.0	ext{ V}$. It is practically throwing its electrons away. This makes it the strongest reducing agent.

**Metal C** has a moderately negative potential of $-1.2	ext{ V}$. It's a decent reducing agent, but not as aggressive as B.

**Metal A** has a positive potential of $+0.5	ext{ V}$. It actually prefers to *gain* electrons rather than lose them. It is the weakest reducing agent of the trio.

### The Final Verdict

Arranging them in decreasing order of their reducing power, we get:
$$ B > C > A $$

This perfectly matches option (a). Remember, in the world of reducing agents, negativity is a superpower!

Animated Solution for Chemistry - Electrochemistry: Standard reduction electrode potentials of three metals $A, B$ and $C$ are $+ 0.5 V, - 3.0 V$ and $- 1.2 V$ , respectively. The reducing power of these metals are

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Visualized Solution

$E_{reduction}^{\circ}$

$Reducing Power$

$Analyzing Given Values$

$Final Order$

The Sigma Insight: Electrochemical Cells

Decoding the Electrochemical Series

The Power to Reduce

Analyzing the Contenders

The Final Verdict

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.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Ereduction∘​

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Reducing Power

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Analyzing Given Values

.math-text-wrapper .katex { font-size: 1.05em !important; } .math-text-wrapper .katex-display { margin: 1rem 0 !important; } Final Order