This is a less than problem.
We start with the balanced equation:
"Ba"("NO"_3)_2 + "Na"_2"SO"_4 → "BaSO"_4 + "2NaNO"_3
Find the limiting reactant
(a) Calculate the initial moles of each reactant
"Initial moles of Ba"("NO"_3)_2 = 0.200 color(red)(cancel(color(black)("L"))) × ("0.35 mol Ba"("NO"_3)_2)/(1 color(red)(cancel(color(black)("L")))) = "0.0700 mol Ba"("NO"_3)_2
"Initial moles of Na"_2"SO"_4 = 0.300 color(red)(cancel(color(black)("L"))) × ("0.2 mol Na"_2"SO"_4)/(1 color(red)(cancel(color(black)("L")))) = "0.060 mol Na"_2"SO"_4
(b) Calculate the moles of "NaNO"_3 from each reactant.
From "Ba"("NO"_3)_2:
"Moles of NaNO"_3 = 0.0700 color(red)(cancel(color(black)("mol Ba"("NO"_3)_2))) × "2 mol NaNO"_3/(1 color(red)(cancel(color(black)("mol Ba"("NO"_3)_2)))) = "0.140 mol NaNO"_3
From "Na"_2"SO"_4:
"Moles of NaNO"_3 = 0.060 color(red)(cancel(color(black)("mol Na"_2"SO"_4))) × "2 mol NaNO"_3/(1 color(red)(cancel(color(black)("mol Na"_2"SO"_4)))) = "0.12 mol NaNO"_3
"Na"_2"SO"_4 is the limiting reactant, because it gives the fewest moles of "NaNO"_3.
Calculate the normality of the "NaNO"_3
At this point we have 0.12 mol "NaNO"_3 in 0.5 L of solution.
If we add another 2 L of water, we have 2.5 L of solution.
"Molarity" = "moles"/"litres" = "0.12 mol"/"2.5 L" = "0.048 mol/L"
Since "1 mol NaNO"_3 = "1 eq NaNO"_3,
"Normality = 0.05 eq/L"