How to Prepare a 5 Molar NaCl Solution: A Comprehensive Guide for Experimenters

Preparation of a 5 molar (5 M) sodium chloride (NaCl) solution is a fundamental skill for any chemistry student or laboratory worker. This guide will walk you through the process of preparing 500 mL of a 5 M NaCl solution, complete with detailed instructions and step-by-step explanations.

Materials Needed

Sodium chloride (NaCl) solid Distilled water A balance A volumetric flask or a graduated cylinder A stirring rod or magnetic stirrer A funnel (optional)

Calculations

To accurately prepare the solution, you must first determine the amount of NaCl needed based on the desired molarity and volume. The formula for molarity (M) is given by:

Molarity (M) (frac{text{moles of solute}}{text{liters of solution}})

Rearranging this formula to solve for moles of solute, we get:

Moles of solute Molarity (M) × Liters of solution

For a 5 M solution in 0.5 L:

Moles of NaCl 5 M × 0.5 L 2.5 moles

Converting Moles to Grams

The molar mass of NaCl is approximately 58.44 g/mol. To convert the moles of NaCl to grams, use the following formula:

Mass of NaCl Moles × Molar mass

For 2.5 moles of NaCl:

Mass of NaCl 2.5 moles × 58.44 g/mol 146.1 g

Preparation Steps

Weigh the NaCl. Using a balance, accurately measure out approximately 146.1 grams of NaCl.

Place the NaCl in a beaker. Add a small amount of distilled water (less than 500 mL) and gently stir until the NaCl is fully dissolved.

Transfer the solution. Once the NaCl is dissolved, carefully transfer the solution to a 500 mL volumetric flask (if not already used).

Add distilled water to the mark. Gradually add distilled water to the volumetric flask until the solution reaches the 500 mL mark.

Mix the solution thoroughly. Shake the volumetric flask gently or stir the solution to ensure homogeneity.

Final Notes

Label the solution with its concentration and the date of preparation to maintain proper documentation. Store the prepared solution appropriately, depending on its intended use, to ensure maximum shelf life and accuracy.

This method will yield a 5 Molar NaCl solution that is ready for use in your experiments or applications!