I have been working on a side project trying to capture carbon dioxide from the atmosphere (more on this another day) and I needed some sodium hydroxide. So I thought, let’s make it!
Sodium bicarbonate (also known as bicarb soda or bicarbonate of soda) is readily available from virtually any grocery store in the baking section. A 500g bag of this should only set you back around $3. If you heat sodium bicarbonate to around 200°C for about an hour, it should release carbon dioxide and water, converting into sodium carbonate.
For each mole of sodium bicarbonate, half a mole of sodium carbonate is produced. So 500g of sodium bicarbonate is about 500 g / 84 g/mol = 5.95 mol. This yields 2.98 mol of sodium carbonate at about 106 g/mol, so around 315 g of sodium carbonate should remain after the reaction is complete. This can be confirmed with a set of scales, and if the product is too heavy, it can go back in the oven until it is done.
Sodium carbonate is relatively soluble, so for the next step dissolve it in water. For 315g of sodium carbonate, around 750mL of water should do the trick. The next step is to convert the sodium carbonate to sodium hydroxide. This can be done by adding calcium hydroxide (also known as hydrated lime) which is readily available from a hardware store. The reaction is as follows
