Standardization Using a Primary Standard

The alternative to the above is using an accurately weighed solid material as the known standard. Such a material is called a primary standard. Thus, a primary standard is a material that can be weighed accurately either for the purpose of preparing a standard solution (which then does not have to be standardized) or for comparison to a solution with which it reacts for the purpose of standardizing that solution. For standardization with a primary standard, Equation (4.21) becomes 

The solution to be standardized is the titrant. In this case, the volume of the titrant must be expressed in liters, as shown. 

The experiment consists of weighing the primary standard on an analytical balance into the titration flask, dissolving, and then titrating it with the solution to be standardized. 

In a standardization experiment, 0.4920 g of primary standard sodium carbonate (Na2C03) was exactly neutralized by 19.04 mL of hydrochloric acid solution. What is the molarity of the HC1 solution Refer to Equation (4.7) for the reaction involved. 

Since the problem concerns molarity, Equation (4.31) applies. 

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