Answer
2.12 M $KNO_{3}$ solution.
Work Step by Step
1 mole of $KNO_{3}=101.1\,g$ of $KNO_{3}$
Moles of $KNO_{3}=75.0\,g\times\frac{1\,mol}{101.1\,g}=0.74184\,mol$
Molarity $M=\frac{\text{moles of solute}}{\text{liters of solution}}=\frac{0.74184\,mol}{0.350\,L}=2.12\,M$
