Question

Potash alum which is used to separate the suspended particles from water, is a double salt of:

• A. potassium and sodium
• B. aluminium and calcium
• C. potassium and aluminium
• D. aluminium and barium

Answer 1

Answer: (C)

potassium and aluminium

Potash alum is another word for the chemical powder of aluminum potassium sulfate. Also known simply as alum or potassium alum. Potash alum is usually used for water purification because it has the ability to stick together negatively charged colloidal parts and alum makes the colloidal particles neutral by making aluminum ions neutral this way pure water is obtained.