2006 chem ce一條mc*

The solution X will get the sodium from both Na2SO4 and NaNO3. The final concentration is as follows:
[X] = (no. of mole of Na in Na2SO4 + no. of mole of Na in NaNO3)/(Vol of Na2SO4 + Vol of NaNO3)

Total mole of Na = 2 x 2 x (100/1000) + (1x 50/1000) = 0.45 mole
Total volume of solution = 100 + 50 = 150cm3

Therefore, the concentration of Solution X is:
[X] = 0.45/150 x 1000 = 3M

The resultant concentration of Na in Solution X is 3M.