About 20 gallons of lemon juice should yield about 1 0 lb of crystallized citric acid.
They are precipitated from their alkaline solutions as cobalt sulphide by sulphuretted hydrogen, but this precipitation is prevented by the presence of citric and tartaric acids; similarly the presence of ammonium salts hinders their precipitation by caustic alkalis.
Moulds have been isolated which occasion the formation of citric acid from glucose.
Considerable trade is done in agro di limone or lemon extract, which forms the basis of citric acid.
The synthesis of citric acid was accomplished by L.