I am trying to make lye or potassium hydroxide. So far I have been leaching ashes in a barrel for a few days. I decided to do some tests on the water to see if it was working. My pH paper said it was basic, so then I reacted it with vinegar to see what would happen. The equation of acetic acid + potassium hydroxide would be this I believe:

$$\ce{KOH + CH3COOH -> CH3COOK + H2O}$$

However, when I mixed the two, it began bubbling after a few seconds. The gas formed smelled like boiled eggs and was white. I assume it is some sulfur compound but I may be wrong. The ashes are mostly from locust wood. Is there anyway to find out what other chemicals are in the ashes and how to separate the potassium hydroxide out?

  • 1
    $\begingroup$ Interesting question. I'm unsure on what smells like "boiled eggs", but you can separate the $\ce{KOH}$ out by precipitating it by adding sodium tetraphenylborate. $\endgroup$ Jun 8, 2017 at 2:13
  • $\begingroup$ Thanks for the tip but I'm trying to make potassium hydroxide from wood ash because I don't have easy access to manufactured chemicals. I'm using it as an electrolyte in electrolysis so I hope the other compounds won't react during that process. $\endgroup$
    – Aeolus
    Jun 8, 2017 at 2:17
  • $\begingroup$ The white you're seeing is probably just condensing water vapor (i.e. steam), especially since you said it was bubbling, which indicates some sort of heating. The smell is probably caused by sulfur compounds like you said, but it's probably not possible to nail down exactly which compounds without some advanced tools. $\endgroup$
    – chipbuster
    Jun 8, 2017 at 2:47
  • $\begingroup$ I thought lye was sodium hydroxide. Sodium is much more prevalent in nature than potassium. What makes you think locust wood would provide potassium hydroxide? $\endgroup$ Feb 28, 2018 at 0:15


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.