Science, Tech, Math › Science Back Titration Definition Share Flipboard Email Print Robert Daemmrich Photography Inc / Corbis via Getty Images Science Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated October 07, 2019 A back titration is a titration method where the concentration of an analyte is determined by reacting it with a known amount of excess reagent. The remaining excess reagent is then titrated with another, second reagent. The second titration's result shows how much of the excess reagent was used in the first titration, thus allowing the original analyte's concentration to be calculated. A back titration may also be called an indirect titration. When Is a Back Titration Used? A back titration is used when the molar concentration of an excess reactant is known, but the need exists to determine the strength or concentration of an analyte. Back titration is typically applied in acid-base titrations: When the acid or (more commonly) base is an insoluble salt (e.g., calcium carbonate) When direct titration endpoint would be hard to discern (e.g., weak acid and weak base titration) When the reaction occurs very slowly Back titrations are applied, more generally, when the endpoint is easier to see than with a normal titration, which applies to some precipitation reactions. How Is a Back Titration Performed? Two steps are typically followed in a back titration: The volatile analyte is permitted to react with an excess reagent A titration is conducted on the remaining quantity of the known solution This is a way to measure the amount consumed by the analyte, thus calculate the excess quantity.