How to Prepare 15% W NaOH

To prepare a 15% (w/v) sodium hydroxide (NaOH) solution, you will need to follow a few straightforward steps to ensure accurate and safe preparation.

1. Gather Materials: You will need sodium hydroxide pellets, distilled water, a scale, a beaker or container, a stirring rod, and personal protective equipment (gloves, goggles).
2. Calculate the Amount of NaOH: A 15% w/v solution means you will have 15 grams of NaOH in every 100 milliliters of solution. For example, if you want to prepare 500 mL of a 15% solution, you will need:
   • 15 grams × 5 = 75 grams of NaOH.
3. Measure the NaOH: Using the scale, accurately weigh out the required amount of sodium hydroxide (75 grams for 500 mL).
4. Add Water: Pour approximately 400 mL of distilled water into the beaker or container first, leaving some space for the addition of NaOH. This is important to help manage the heat produced when NaOH dissolves in water.
5. Dissolve the NaOH: Slowly add the measured NaOH pellets to the water while constantly stirring with a stirring rod. Always add NaOH to water and not the other way around to prevent exothermic reactions that can cause splattering.
6. Adjust the Volume: After the NaOH is completely dissolved and the solution has cooled, add additional distilled water to bring the total volume up to 500 mL.

It’s important to handle sodium hydroxide with care, as it is highly caustic and can cause severe burns. Always wear appropriate safety gear and work in a well-ventilated area.