I have a container with NaOH granulate. I want to use it for making soap again, as I did in the past.
When I checked it I saw big clumps because the seal was not good and humidity got in since last time. Yesterday I used it anyway, increasing the amount arbitrarily by 10%, and still was not enough.
I have the following tools:
- scale (sensitivity 1 gram),
- arbitrary glass or plastic volume meter calibrated with said scale,
- temperature probe (up to 70C with 0.5C tolerance and 0.1C sensitivity),
- white vinegar,
- concentrated lemon juice,
- concentrated HCl (I think 36%).
More common "kitchen" chemicals may be available, if you ask in the comments.
How can I estimate how much humidity is present in the NaOH granulate using household items/chemicals?
A measurement performed directly on the NaOH solution used for the soap (around 300 g NaOH and 750 g water) is acceptable.