Potassium bicarbonate dry chemical fire extinguishers, as the principal component of the Purple-K dry chemical, and in some applications of condensed aerosol fire suppression. It is the only dry chemical fire suppression agent recognized by the U.S. National Fire Protection Association for firefighting at airport crash rescue sites. It is about twice as effective in fire suppression as sodium bicarbonate. Potassium bicarbonate is an effective fungicide against powdery mildew and apple scab, allowed for use in organic farming. Potassium bicarbonate has widespread use in crops, especially for neutralizing acidic soil. The word "saleratus", from Latin "sal æratus" meaning "aerated salt", was widely
Potassium chromate Potassium chromate Potassium chromate is the inorganic compound with the formula (KCrO). This yellow solid is the potassium salt of the chromate anion. It is a common laboratory chemical, whereas sodium chromate is important industrially. It is a class two carcinogen as it contains hexavalent chromium. Two crystalline forms are known, both being very similar to the corresponding potassium sulfate. Orthorhombic β-KCrO is the common form, but it converts to an α-form above 66 °C. These structures are complex, although the sulfate adopts the typical tetrahedral geometry. It is prepared by treating potassium dichromate with potassium hydroxide. In solution, the