How much more sodium, in grams, is in a 3m solution than 2m soultion?

23 grams Na

Thus, 3 M = 3 moles/liter

         2 M = 2 moles /liter

The difference is 1 mole/Liter

But, 1 mole of sodium 23 g

Therefore;

Mass of sodium = moles × Atomic mass

                           = 1 mole × 23 g/mol

                           = 23 g

Therefore a 3 M solution contains 23 g of sodium more than a 2 M solution.