Question

State whether the following statements are true or false. In the electrochemical series, ions are arranged in an increasing order of discharge potentials.

Short answer

Answer: False

Step-by-step solution

Understanding the Electrochemical Series

The electrochemical series is a list of elements or ions arranged in order of their standard electrode (reduction) potentials, which refers to their ability to accept or lose electrons. In this series, the more positive the reduction potential, the higher the tendency of the ion to accept electrons and be reduced. Conversely, the more negative the reduction potential, the higher the tendency of the ion to lose electrons and be oxidized.

Discharge Potentials

Discharge potential is the minimum potential required to discharge an ion (the limit at which it changes its state from an ion to an atom by electron transfer). In the electrochemical series, elements that have a higher reduction potential are more likely to be reduced and will therefore have a low discharge potential, while those with a lower reduction potential will have higher discharge potentials.

True or False

Now, we need to determine whether the ions in the electrochemical series are arranged in an increasing order of discharge potentials. Since elements with higher reduction potentials have lower discharge potentials, the series is not arranged in an increasing order of discharge potentials, but rather, in an increasing order of reduction potentials. So, the statement "In the electrochemical series, ions are arranged in an increasing order of discharge potentials" is False.

Key concepts

Reduction Potential

In the realm of electrochemistry, reduction potential is a crucial concept. It measures the tendency of a chemical species to gain electrons and be reduced. Each element or ion has a standard reduction potential, a value usually measured in volts.

A positive reduction potential indicates a strong tendency to gain electrons and reduce. Conversely, a negative value suggests a tendency to lose electrons, becoming oxidized instead. For example:

• Copper has a positive reduction potential, showing it readily accepts electrons.
• Zinc, on the other hand, comes with a negative value, favoring electron loss.

This concept helps to arrange elements in the electrochemical series, enabling predictions about redox reactions.

Discharge Potential

Discharge potential focuses on the energy needed for ions to convert from their ionic state to a neutral atom through electron transfer. It corresponds to the threshold potential at which an ion undergoes this transformation.

The higher the discharge potential, the more energy is needed to discharge the ion. However, ions with higher reduction potentials typically have lower discharge potentials, meaning they require less energy to gain electrons and be reduced.

In essence, while reduction potential reveals the inclination to gain electrons, discharge potential quantifies the energy necessary to complete electron transfer.

Electrode Potential

Electrode potential, often interchangeably called reduction potential, reflects the potential difference created when a half-cell in an electrochemical series reaches equilibrium. It's essentially the voltage produced by a half-cell.

• The standard condition involves 1M concentration and a pressure of 1 atm.
• Measured against the standard hydrogen electrode, this helps in determining how likely an electrode will undergo reduction.

Changes in electrode potentials illustrate how conditions, like temperature and concentration, can influence redox reactions. Such insights are critical in designing effective electrochemical cells.

Electron Transfer

Electron transfer lies at the heart of electrochemical processes. It involves the movement of electrons between two entities, typically occurring in redox reactions.

In the electrochemical series, electron transfer happens when ions gain or lose electrons to form neutral atoms or different ions. Such transfers are crucial since they determine the direction of metal ion reduction or oxidation.

• During reduction, elements gain electrons. This is an electron transfer from the anode half-cell, which gets oxidized.
• In oxidation, electrons are lost, transferred to the cathode where reduction occurs.

Electron transfer is fundamental, underpinning technologies from batteries to corrosion protection.