What does the letter “C” on the bottle label mean?

There are thousands of types of chemical reagents with different properties. The reagent bottle label is set to distinguish different types of reagents. Different letters represent different types of reagents, and the letter “C” represents corrosive chemical reagents.
Corrosive reagents refer to reagents that are corrosive to skin, mucous membranes, eyes, respiratory organs, etc., including liquids and solids. For example, sulfuric acid, hydrochloric acid, hydrobromic acid, phosphoric acid and nitric acid among inorganic acids, carboxylic acid and sulfonic acid among organic acids are all corrosive. Phenol is also quite dangerous, can cause skin burns, and its toxic vapor can be absorbed by the skin. Strong bases such as sodium hydroxide and potassium hydroxide in inorganic bases and weak bases such as sodium sulfate and potassium sulfate are all corrosive, and amines, hydroxylamine, triethylamine, and pyridine in organic bases are all corrosive.
Liquid bromine is a very dangerous drug, it can cause burns to the skin and eyes, so be sure to use it in a fume hood. In addition, due to its high density, when transferring with a dropper, even if the latex tip is not squeezed, it may drip due to its gravity, so be careful when using it. Thionyl chloride, acid chloride, anhydrous aluminum trichloride and some other reagents are also corrosive because they can react with water to release hydrogen chloride gas, and can cause serious irritation to the respiratory system.
If the letter “C” on the label of the reagent bottle indicates that the bottle contains corrosive reagents, be sure to wear protective gloves when handling or using such reagents. If splashed on skin, rinse immediately with plenty of water.