... occur caramel smell. (2) sample solution with 4.3% sodium hydroxide solution to neutral, plus 5% sulfuric acid solution heated ... . Take this solution, part of the added 4.3% sodium hydroxide solution, insoluble precipitate; part by adding 24% hydrochloric acid, ... . (5) This product should not be preservative potassium sorbate, sodium potassium solution, such as benzene, while adding, if necessary, ...