In the process of bleaching by means of chlorine either bleaching powder or bichromates and hydrochloric acid are used.
BICHROMATES AND CHROMATES.
In addition to these normal salts, others exist, namely bichromates, trichromates, &c., which may be regarded as combinations of one molecular proportion of the normal salt with one or more molecular proportions of chromium trioxide.
The bichromates are usually of a red or reddishbrown colour, those of the alkali metals being readily soluble in water.
The chromates of sodium, potassium and ammonium, as well as the bichromates of potassium and ammonium, were found to give the same absorption spectrum.