Preparing a 1 L 18 NaOH Solution from a 50% Stock Solution

Are you working in a laboratory and need to prepare a 1-liter 18 NaOH (sodium hydroxide) solution using a 50% stock solution? This guide will walk you through the process step-by-step, ensuring accuracy and safety throughout the preparation.

Introduction to Solution Preparation

Sodium hydroxide (NaOH) is a highly caustic substance, commonly known as lye, and is widely used in various applications including cleaning, pH adjustment, and chemical processing. Proper preparation ensures the solution is safe to handle and meet specific concentration requirements.

Step-by-Step Guide

Step 1: Calculate the Amount of NaOH Required

To prepare a 1-liter (1000 mL) solution of 18% NaOH, first determine the amount of NaOH needed in grams.

mass of NaOH volume times; concentration

mass of NaOH 1000 mL times; 0.18 g/mL 180 g

Step 2: Calculate the Volume of 50% NaOH Solution Needed

The 50% NaOH solution means there are 50 grams of NaOH in every 100 mL of solution. To find the volume required to obtain 180 g of NaOH, use the following calculation:

Volume of 50% solution (mass of NaOH / concentration of 50% solution) times; 100

V (180 g / 50 g/100 mL) times; 100 360 mL

Step 3: Prepare the Solution

Measure out 360 mL of the 50% NaOH solution using a graduated cylinder or burette. Carefully add distilled water to bring the total volume up to 1000 mL.

Total volume of distilled water needed 1000 mL - 360 mL 640 mL

Summary

To prepare 1 liter of an 18% NaOH solution:

Use 360 mL of 50% NaOH solution Add 640 mL of distilled water

Note: Always wear appropriate safety gear such as gloves and goggles when handling NaOH as it is a caustic substance.

Additional Information

For further precision, let's consider some additional calculations. The density of a 50% NaOH solution is 1.5253 g/mL, and for the 18% solution, it is 1.1971 g/mL.

Calculation using density:

m m/m * D * V

V1 (0.5 * 1.5253 * V1) / (0.18 * 1.1971 * 1000 mL) 282.54 mL

V (1000 * 18) / 50 360 mL

Conclusion:

In both methods, the volume of the 50% NaOH solution required to prepare a 1 liter 18% NaOH solution is 360 mL, and the remaining volume to be filled with distilled water is 640 mL.