Any lead chloride dissolves, and may be identified by the yellow precipitate formed with potassium chromate.
The vermilion-like pigment which occurs in commerce as "chromered" is a basic chromate, Pb2Cr05, prepared by treating recently precipitated normal chromate with a properly adjusted proportion of caustic soda, or by boiling it with normal (yellow) potassium chromate.
Solutions of lead salts (colourless in the absence of coloured acids) are characterized by their behaviour to hydrochloric acid, sulphuric acid and potassium chromate.
The yellow solution is made up of i part of neutral potassium chromate in 199 parts of water, and to give the various degrees of the scale, 1, 2, 3, 4, &c.,% of the yellow solution is mixed with 99, 9 8, 97, 96, &c.,% of the blue in successive tubes.
Chlorides can be estimated quantitatively by conversion into silver chloride, or if in the form of alkaline chlorides (in the absence of other metals, and of any free acids) by titration with standard silver nitrate solution, using potassium chromate as an indicator.
