Normality in chemistry is the grams of solute in a particular solution. To calculate normality you need to consider the following:
1. There are to moles of sodium for every one mole of carbonate. The molarity for the solution is 1(CO3)/2(Na)= 0.5 moles
2.To determine the amount of moles required for the solution, we must consider the volume of the solution.
5L x 0.5 moles = 2.5 moles
3. Since we know that there is 98% of Na2CO3 in the solution, we assume that there 98g out of 100g. Molar mass of Na2CO3 is 106g/mole Then to find the total amount of grams in the solution, we must do the following:
Find molar mass of solute: 2.5 moles x 106 g/mole = 265 grams of Na2CO3
Then, 265 g x 98g/100g= 270.4 grams of Na2CO3