Principles of Volumetric Analysis

The equivalence point is reached when the quantity of titrant added is the exact amount necessary for stoichiometric reaction with the analyte. For example, 5 mol of oxalic acid react with 2 mol of permanganate in hot acidic solution  

If the unknown contains 5.00 mmol of oxalic acid, the equivalence point is reached when 2.00 mmol of MnO have been added. 

The equivalence point is the ideal result that we seek in a titration. What we actually measure is the end point, which is marked by a sudden change in a physical property of the solution. For Reaction 6-1, a convenient end point is the abrupt appearance of the purple color of permanganate in the flask. Up to the equivalence 

We will study end-point detection methods later  

Box 3-1 describes Standard Reference Materials, which allow different laboratories to test the accuracy of their procedures. 

---

In this chapter we review the fundamental concepts of mass, moles, and equivalents the ways in which analytical results may be expressed for solids and liquids and the principles of volumetric analysis and how stoichiometric relationships are used in titrations to calculate the mass of analyte. 

---