Question

describe the preparation of : 250ml of 0.1N (Na2Co3) from the solid reagent.

Answer 1

The equivalent weight of Na₂CO₃ is 53. For 0.1 N solutionof Na₂CO₃ we need
0.1*53 = 5.3 g of Na₂CO₃ for 1 L.
For 0.25 L of solution we need
0.25*5.3 = 1.325 g of Na₂CO₃.

Thus, we should weigh 1.325 g of Na₂CO₃ and transfer it into the 250 mL volumetric flask and add water to below the neck portion of the flask to dissolve the solid. If you shake the flask to help dissolve the solid, make sure the stopper is in place. After the solid is completely dissolved, very carefully fill the flask to the mark.