# How do you make a 600*mL volume of 20%*("w/w") caustic soda in water?

Apr 7, 2017

Measure a mass of $60 \cdot g$ caustic soda........
Measure a mass of $60 \cdot g$ caustic soda........and be quick because the stuff deliquesces in air (note that at a minimum you should be wearing safety spectacles to protect your mince pies, and avoid skin contact with the pellets). And pour in a measured volume of water, approx. $50 - 60 \cdot m L$. The solution, $\text{the lye}$, will get hot as the sodium hydroxide dissolves; the heat of solution (and it will get very hot) should get all the solute into solution. Once the pellets have dissolved, make up the volume to $600 \cdot m L$.
"Concentration"="Mass of NaOH"/"Volume of solution"=(60*g)/(300*g)xx100%=
=1/5xx100%=20%.