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.