Method A: The salinity can be measured by titration in the laboratory using a silver nitrate solution.Calculate the salinity of the freshwater sample using the formula: Salinity (PSU)= [Cl] x 1.805 +0.03 the titrating solution of silver nitrate (AgNO3) is made in such a way that 2 ml of it corresponds to 1 g of Cl per kg of water.The indicator solution will turn the sample yellow.