Question

Is the following statement true or false? Concentration cells work because standard reduction potentials are dependent on concentration. Explain.

Short answer

The statement "Concentration cells work because standard reduction potentials are dependent on concentration" is false. Concentration cells work due to the concentration gradient of ions in the solution, and while the Nernst equation allows us to account for changes in concentration when determining the actual cell potential, the standard reduction potentials themselves do not change with concentration.

Step-by-step solution

Understand Concentration Cells

: A concentration cell is a type of electrochemical cell in which both electrodes are made of the same material, and the only difference between the two half-cells is the concentration of the ion in the solution. The spontaneous redox reaction in this cell generates an electric current due to the concentration gradient of the ions.

Understand Standard Reduction Potentials

: Standard reduction potential is the tendency of a chemical species to gain electrons and undergo reduction. It is measured under standard conditions (25°C, 1 atm, and 1M concentration). The standard reduction potential represents the cell potential of a particular electrode when connected to a standard electrode (usually the hydrogen electrode) under standard conditions.

Understand the relationship between concentration and standard reduction potentials

: Standard reduction potentials, by definition, are measured under standard conditions, meaning that the concentration of the ions is taken to be 1M. However, in real-world electrochemical systems, concentrations are not always 1M. The Nernst equation allows us to determine the actual cell potential of the system under non-standard conditions by considering changes in concentration. The Nernst equation: \(E = E° - \frac{RT}{nF} \ln Q\) In this equation, E is the cell potential, E° is the standard cell potential, R is the ideal gas constant, T is the temperature, n is the number of moles of electrons transferred, F is the Faraday constant, and Q is the reaction quotient.

Evaluate the provided statement

: The given statement is that concentration cells work because standard reduction potentials are dependent on concentration. This statement is partially accurate, but not entirely true. Concentration cells work due to the concentration gradient of the ions present in the cell, which generates an electric current. The Nernst equation allows us to account for the changes in concentration in determining the actual cell potential. However, the standard reduction potentials themselves are measured under standard conditions and, by definition, do not change with concentration. Therefore, the statement is false. In conclusion, the statement "Concentration cells work because standard reduction potentials are dependent on concentration" is false. Concentration cells work due to the concentration gradient of ions in the solution, and while the Nernst equation allows us to account for changes in concentration when determining the actual cell potential, the standard reduction potentials themselves do not change with concentration.