Final answer:
The method of adding a solution of known concentration to another of unknown concentration for analysis is known as titration analysis (Option C). It involves using a known reagent, the titrant, to determine the concentration of an analyte in a solution through stoichiometric calculations at the equivalence point.
Step-by-step explanation:
The technique where a solution of known concentration is slowly added to a solution of unknown concentration is commonly used in titration analysis. In a titration, a reagent known as the titrant, which has a known concentration, is precisely added to a solution containing the analyte, whose concentration is unknown. This is carried out using a burette, which allows accurate measurement of the volume of titrant added.
When the reaction reaches the equivalence point, where the titrant and analyte have reacted stoichiometrically, the volume of titrant added is used to calculate the concentration of the analyte based on the balanced chemical equation. This quantitative chemical analysis is distinct from gravimetric analysis, which involves the separation and mass measurements of components, and from spectroscopic and electrochemical analyses, which use different principles for the determination of analyte concentration.
Therefore, the common method in chemical analysis where a solution of known concentration is slowly added to a solution of unknown concentration is C) Titration analysis.