Final answer:
The molarity of the solution is 0.680 M KNO₃. Therefore, the correct answer is option a.
Step-by-step explanation:
To determine the molarity of a solution, we need to use the formula: Molarity (M) = moles of solute / volume of solution (in liters). First, we need to calculate the number of moles of KNO₃. The molar mass of KNO₃ is 101.11 g/mol. Therefore, the number of moles is: moles = mass / molar mass = 29.2 g / 101.11 g/mol = 0.289 mol.
Next, we need to convert the volume of the solution from milliliters to liters. There are 1000 milliliters in 1 liter, so the volume is: volume = 425 mL / 1000 mL/L = 0.425 L. Finally, we can calculate the molarity: Molarity = moles / volume = 0.289 mol / 0.425 L = 0.68 M KNO₃ .