Science Buddies: "Ask an Expert"

How do i prepare 2% of sodium hydroxide solution?

Thanks

Hello there!
I'm assuming that you mean the concentration is 2% mass/volume, which means 2 grams sodium hydroxide per 100 mL solution. (If my assumption is wrong, let me know). Here are the procedures for making a 100 mL of 2% m/v solution.

1. Calculate the mass of sodium hydroxide required for making 100.0 mL of solution.
(concentration)(desired volume) = required mass solute
(2 grams NaOH/100.0 mL solution)(100.0 mL solution) = 2.00 grams NaOH
2. Weigh out the required mass of NaOH in a weigh boat on a balance.
3. Add approximately half the desired volume (50.0 mL in this case) of distilled water to a clean 100.0 mL graduated cylinder (volumetric flask would also work).
4. Add the weighed-out NaOH into the graduated cylinder.
5. Rinse the weight boat and sides of the graduated cylinder with distilled water to ensure all NaOH residue is IN solution. ("Rinse the weigh boat" means adding distilled water to the weight boat to remove all residue, then adding the resulting liquid to the main solution).
6. Swirl to dissolve NaOH.
7. Bring volume up to 100.0 mL with distilled water.
8. Label storage bottle.
9. Transfer and store.

If you want to make larger quantities, just change the "desired volume" in the calculation of step one. Also, if you don't have the exact equipment in these procedures, you can ask questions for alternatives.

I hope that helps!
Kayli Masuda