What principle is titration based on?

Titration is a quantitative analytical method used to determine the concentration of a particular substance in a solution by the gradual addition of a reactant, known as a titrant, until the reaction reaches its endpoint. This endpoint is often indicated by a color change or a measurable change in some property of the solution. The process relies on measuring how much titrant is required to completely react with the analyte present in the solution.

The principle focuses on the careful addition of the titrant, which allows for precise control over the reaction conditions and enables accurate calculations of the concentration of the unknown solution. This method relies heavily on the stoichiometric relationships between reactants and products in a chemical reaction, making it an essential technique in analytical chemistry.

In contrast, the other options do not pertain directly to the core concept of titration. The conservation of energy relates more to thermodynamics, measurement of reaction temperature is relevant for certain types of reactions but is not a defining principle of titration itself, and the evaporation of solvents is unrelated to the process of adding a titrant to a solution. Thus, the correct focus here is the gradual addition of a reactant, which is fundamental to the process of titration.