Question

A solution contains 2.65g of anhydrous Na2O3 in 200cm³ of the solution. Calculate the concentration of the solution in g/dm³ given that (Na2CO3 = 106)

Answer 1

I think you must have meant to calculate the molarity; however, you said g/dm^3 so
2.65 g x (1 dm^3/0.2 cm^3) = ?

Answer 2

Calculate the conc of the solution in g/dm^3

Answer 3

That's what I gave you but I made a typo. That .2 cm^3 should have been 0.2 dm^3.
2.65 g x (1 dm^3/0.2 cm^3) = ?
In any event, the answer is the same.