## Nernst Equation – Class 12 | Chapter – 3 | Chemistry Short Notes Series PDF for NEET & JEE

Nernst Equation: The Nernst equation is a mathematical equation that relates the electrochemical potential of a half-cell to the concentration of its constituent ions. The equation is named after Walther Nernst, a German physical chemist who derived the equation in 1889.

## Nernst Equation

The Nernst equation is used to calculate the electrochemical potential of a half-cell under non-standard conditions, i.e., when the concentrations of the ions in the half-cell are not at their standard state. The equation can be used to calculate the potential of a cell in which two half-cells are connected through a salt bridge or porous membrane, such as in a galvanic cell. The Nernst equation is an important tool in electrochemistry and is used to design and optimize electrochemical systems, including batteries, fuel cells, and sensors. The Nernst equation is given by:

E = E° – (RT/nF) * ln(Q)

where:

• E is the electrochemical potential of the half-cell
• E° is the standard electrochemical potential of the half-cell
• R is the gas constant (8.314 J/mol·K)
• T is the temperature in Kelvin
• n is the number of electrons transferred in the half-reaction
• F is the Faraday constant (96,485 C/mol)
• Q is the reaction quotient, which is the ratio of the product concentrations to the reactant concentrations, each raised to their stoichiometric coefficients.

## Applications of Nernst Equation

The Nernst equation is a fundamental tool in electrochemistry, and it has numerous applications in various fields, including:

• Electrochemical Cells: The Nernst equation is used to calculate the cell potential of electrochemical cells. It is used to determine the concentration of reactants and products in the half-cells of a cell.
• Corrosion: The Nernst equation is used to calculate the corrosion potential of metals and alloys under different conditions.
• Sensors: The Nernst equation is used in the design and optimization of electrochemical sensors. The equation helps in determining the sensitivity and selectivity of sensors.
• Battery Design: The Nernst equation is used to design and optimize batteries. It is used to calculate the theoretical cell voltage and to determine the factors that affect battery performance.
• Biochemistry: The Nernst equation is used to calculate the resting membrane potential of cells. It is used to determine the concentration of ions, such as sodium, potassium, and chloride, inside and outside of cells.
• Environmental Science: The Nernst equation is used to study the redox reactions that occur in environmental systems, such as water and soil. It is used to determine the concentration of pollutants in these systems.
• Industrial Processes: The Nernst equation is used in industrial processes such as electroplating, metal refining, and wastewater treatment. It is used to optimize these processes by determining the concentration of reactants and products.

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