Which of the following is the correct procedure to prepare 1.0 M solution of KNO3 in water?

• A. Dissolve 101.1 g of KNO3 in 100 mL of water.
• B. Dissolve 101.1 g of KNO3 in enough water to make a final volume of 1.00 L.
• C. Dissolve 1.0 g of KNO3 in 1.00 L of water.
• D. Add 101.1 g of KNO3 to 1.00 L of water.

Answer: (B)

Verified step by step guidance

1. Understand that molarity (M) is defined as moles of solute per liter of solution, not per liter of solvent. The formula is \(M = \frac{\text{moles of solute}}{\text{liters of solution}}\).
2. Calculate the number of moles of KNO\_3 needed for a 1.0 M solution in 1.00 L of solution using the molar mass of KNO\_3 (approximately 101.1 g/mol). The moles required are \$1.0 \text{ mol/L} \times 1.00 \text{ L} = 1.0 \text{ mol}$.
3. Convert moles to grams by multiplying the moles by the molar mass: \$1.0 \text{ mol} \times 101.1 \text{ g/mol} = 101.1 \text{ g}$ of KNO\_3.
4. Recognize that to prepare the solution correctly, you must dissolve 101.1 g of KNO\_3 in enough water to make the total volume exactly 1.00 L, not just add it to 1.00 L of water or dissolve it in a smaller volume of water.
5. Therefore, the correct procedure is to dissolve 101.1 g of KNO\_3 in water and then add more water until the total volume of the solution is 1.00 L.