Question

Given below are few statements regarding electrode potentials. Mark the correct statements. (i) The potential associated with each electrode is known as electrode potential. (ii) A negative \(E^{\circ}\) means that the redox couple is a stronger reducing agent than \(\mathrm{H}^{+} / \mathrm{H}_{2}\) couple. (iii) A positive \(E^{\circ}\) means that the redox couple is a weaker reducing agent than \(\mathrm{H}^{+} / \mathrm{H}_{2}\) couple.

Short answer

All statements (i), (ii), and (iii) regarding electrode potentials are correct.

Step-by-step solution

Understanding Electrode Potentials

The electrode potential is the ability of an electrode to gain or lose electrons, and is measured in volts. It indicates the tendency of an electrode to be oxidized or reduced.

Analyzing Statement (i)

Statement (i) says 'The potential associated with each electrode is known as electrode potential.' This statement is correct as it correctly defines electrode potential.

Analyzing Statement (ii)

Statement (ii) mentions 'A negative \(E^{\circ}\) means that the redox couple is a stronger reducing agent than \(\mathrm{H}^{+} / \mathrm{H}_{2}\) couple.' This is true since a negative standard electrode potential implies a greater tendency to donate electrons compared to the hydrogen standard.

Analyzing Statement (iii)

Statement (iii) states 'A positive \(E^{\circ}\) means that the redox couple is a weaker reducing agent than \(\mathrm{H}^{+} / \mathrm{H}_{2}\) couple.' A positive \(E^{\circ}\) indeed indicates that the substance is less likely to donate electrons compared to the hydrogen couple, making it a weaker reducing agent, so this statement is also correct.

Key concepts

Standard Electrode Potential

Imagine you've got two friends, one is really into giving away stickers, while the other prefers to hold onto theirs. In the world of chemistry, this kind of behavior can be measured, and we call this measurement the standard electrode potential (\( E^\text{o} \)). It tells us how much an electrode “wants” to give away or take electrons when it’s in its most comfortable, or 'standard' state (which means the temperature is a cozy 25°C, the pressure is just right at 1 bar, and the solutions are at an even 1 molar concentration).

If the standard electrode potential is a positive number, think of it as the sticker-hoarding friend; the electrode doesn't really want to give away its electrons. However, if it's a negative number, now we're talking about the generous friend, ready to donate those stickers (or electrons, in the chemistry world) to others. This generosity or reluctance helps scientists figure out how different substances will behave in a reaction, especially during those give-and-take scenarios called redox reactions.

Reducing Agent

Speaking of generosity, let's talk about the bighearted buddy in the chemical world: the reducing agent. A reducing agent is like the friend who always insists on paying for your coffee. They give away something valuable—in the case of chemistry, it's electrons—without expecting anything in return. When a substance donates electrons to another one, it's doing a noble task of reducing the other substance. But there's a catch! While it's making the other substance gain electrons and become reduced, the reducing agent itself gets oxidized.

Think of it like a balance scale, where electrons are shared between two sides. If one side gives electrons (the reducing agent), it becomes lighter, while the other side that receives the electrons (the oxidized material) becomes heavier. The more eager a substance is to give up its electrons, the better a reducing agent it is. This eagerness is often linked to the standard electrode potential we just talked about—negative values mean more eagerness to be the reducing agent.

Oxidation-Reduction Reactions

When someone shares a secret with you, it changes the relationship, right? Similarly, in the chemistry cosmos, every time electrons are shared or transferred, it changes the substances involved. This process is called an oxidation-reduction reaction, or 'redox' for short. It’s like a dance, where one partner (the reducing agent) passes an electron to the other partner (the oxidized species), and they both change their moves, or oxidation states, in the process.

Understanding redox reactions is super important because they're the backbone of many processes in our world, from breathing to batteries. In essence, anytime you see a chemical suddenly grabbing electrons or dramatically giving them away, you're witnessing the dance of a redox reaction. These reactions help us keep track of who’s losing electrons (oxidation) and who’s gaining (reduction), which is crucial for predicting the outcomes of many scientific experiments and industrial processes.