### An example for practicing

You have to blindly control two yogurts. You know that one of them is a classic yogurt, while the other is a protein-rich yogurt. To this end, you carry out a determination of total nitrogen for each of the products (A and B) by the Kjeldahl method (see experimental procedure).
• the initial test sample mass (mproduct) is 1.035 g for each yogurt.
• the titration volumes of NaOH 0.1 mol/L (Vsample) are 20.4 mL for yogurt A and 15.9 mL for yogurt B.
• the titration volume of NaOH for the control (Vcontrol) is 25.1 mL.
The formula for determining the protein content in a product, in g for 100 g of product, is:
Yogurt A is the protein-rich yogurt.
The protein content in yogurt A, in g for 100 g of product, is:
The protein content in yogurt B, in g for 100 g of product, is:
If you are presented with a third yogurt (yogurt C), which is said to be half as high in protein as the classic yogurt, what volume of sodium hydroxide (0.1 mol/L) would you expect to pour to verify this information if the mass of the initial sample is 1.000 g?
Correction