#293130 April 2020Chem Lab Tuesday 11:00amUnknown Weak Acid TitrationTitrations can be used for a variety of investigations; one being the discovery of the concentration of an unknown species. This unknown is plays the role of the analyte. By completing a titration, the point of equivalence can be determined. This point indicates the completion of the reaction and lies in the middle of the buffer region which is indicated by a steep incline on the titration curve and represents the pKavalue ±1pH. Equivalence allows us to evaluate the molar concentrations of all species of the reaction at that point. This will present the molar amount of the unknown acid originally present in the solution. Using this information, molar mass can be calculated using a gmolconversion. The acid in this investigation is a monoprotic acid meaning there is a 1:1 stoichiometry ratio between all speciesand their molar mass is equal to their equivalent mass. These concepts also come into play when using the Kavalue of an acid. This value determines the strength of an acid. The smaller the Kavalue, the weaker the acid and vice versa. The negative log of this value will yield the pKavalue of the acid which can be inserted into the Henderson-Hasselbalch equation, pH=pKa+logbaseacid, to find pH of the acid. These concepts and relationships between them are what guide us in answering the question, “What is the identity of the unknown weak acid?”
