How many sodium ions are in the initial 50 ml solution of na2co3?

The mass of the solute that is being dissolved here is 7.15 g Na2CO3-10H2O (found on other sources). We use this amount to convert it to moles of Na2CO3. And by the dissociation of the salt in the solution, we can calculate the moles of Na+ ions are present.

Na2CO3 = 2Na+ + CO3^2-

7.15 g Na2CO3-10H2O ( 1 mol / 286 g) ( 1 mol Na2CO3 / 1 mol Na2CO3-10H2O ) ( 2 mol Na+ / 1 mol Na2CO3) = 0.05 mol Na+ ions present

So what you would do is go through and add 3 teaspoons(tsp) 6 times because of the 6 tablespoons(tbsp). which will give you an answer of 18. another way is to multiply 3x6=18.

Yeah, but what are you trying to ask?