Description: White crystalline powder, free from extraneous Matter with a faint odour of sulphur dioxide gas. Our Potassium Meta Bisulphite is used as a photographic chemical, dyes intermediate and preservative chemical. These are white free-flowing powder, free from foreign particles. Our range is widely appreciated by clients due to accurate composition, precise pH value, purity and effectiveness. Potassium Metabisulphite, K2S2O5, also known as potassium pyrosulfite, is a white crystalline powder with a pungent odour. It is mainly used as an antioxidant or chemical sterilant. As a disulfite, it is chemically very similar to sodium Metabisulphite, with which it is sometimes used interchangeably.