The reaction rate constant can be defined as the rate of reaction when each reactant's concentration is

The correct answer is Unity.

Key Points

• The reaction rate constant (k) is defined as the rate of reaction when the concentration of each reactant is kept at unity (1 mol/L).
• It provides a measure of the intrinsic speed of a chemical reaction, independent of reactant concentrations.
• The rate constant is specific to a particular reaction and depends on temperature and the presence of a catalyst.
• It is denoted by "k" in rate equations and varies for different orders of reactions (e.g., zero-order, first-order, second-order).
• The units of the rate constant depend on the reaction order; for example, s^-1 for first-order reactions and L·mol^-1·s^-1 for second-order reactions.

Additional Information

• Rate Equation: The rate of a chemical reaction is represented as Rate = k [A]^m[B]ⁿ, where m and n are reaction orders for reactants A and B.
• Arrhenius Equation: The rate constant k is temperature-dependent and can be expressed as k = A·e^-Ea/RT, where A is the pre-exponential factor, Ea is the activation energy, R is the gas constant, and T is the absolute temperature.
• Reaction Order: The sum of the powers of the concentration terms in the rate equation determines the reaction order (e.g., first-order, second-order).
• Units of Rate Constant: For zero-order reactions, k has units of mol·L^-1·s^-1; for first-order reactions, s^-1; and for second-order reactions, L·mol^-1·s^-1.
• Factors Influencing Rate Constant: Temperature, the presence of a catalyst, and the nature of the reactants affect the magnitude of the rate constant.