The correct option is B KHCO3 is too soluble to be precipitated by KCl and NH4HCO3
Solvay process cannot be used to prepare potassium carbonate. This is because, unlike sodium bicarbonate, potassium bicarbonate is fairly soluble in water and does not precipitate out i.e., KHCO3 is too soluble to be precipitated by KCl and NH4HCO3.