Potassium is not prepared by Solvay process because …X… is too soluble to be precipitated by addition of ammonium hydrogen carbonate. Here, X refer to

Solvay process can’t be used to the manufacture of potassium carbonate because potassium hydrogen carbonate is too soluble be precipitated by the addition of ammonium hydrogen carbonate hence, potassium carbonate cannot be prepared by Solvay process.