Hydrochloric Acid Test

Hydrochloric acid of 50% strength is added to powdered lime kept in a test tube till effervescence ceases. Generally, a teaspoonful of powdered lime of about 10 cc is required. It is kept for 24 hours. The bubbling reaction indicates the presence of lime. The volume of insoluble residue signifies unwanted inert material.

Class A lime shows the formation of good thick gel after 24 hours of letting the mixture stand. Class B lime shows the formation of gel, whereas no gel is formed in the case of Class C lime.