Potassium aluminium sulfate
Potassium aluminium sulfate, or potash alum, or potassium alum, is a chemical compound. Its chemical formula is KAl(SO4)2. It contains potassium, aluminium, and sulfate ions. Crystals of it are transparent, and it is white when made into a powder.
Properties
It is a acidic solid at room temperature. It does not have a colour; its crystals are transparent, and its powder is white. It reacts with sodium bicarbonate to make carbon dioxide gas. It exists naturally, and can be found as a mineral.
Preparation
It is made by reacting aluminium sulfate with potassium sulfate.
Uses
It is used to purify water. It is also used in deodorants. It is an antiseptic. It had several uses in the past, such as in dyeing clothes. Crystals can be grown from a solution of potassium aluminium sulfate.
Potassium Aluminium Sulfate Media
Octahedral potassium alum crystal with unequal distribution of the face area
An alum block sold as an astringent in pharmacies in India (where it is widely known as Fitkiri (Bengali), Fitkari (Hindi) or Phitkari (Urdu)
