Pyrogallic acid | Metagallic acid | Black residue, insoluble in water. (C_{6}H_{3})HO_{3}| | Molec. Wt. 126 | | | | Silver nitrate, | Free nitric acid | Reddens litmus paper. (Neutral AgNO_{3} | | silver nitrate does not Molec. Wt. 170 | | affect litmus.) | | Potassium | Chlorides and | Same as for ammonia. carbonate | sulphates | K_{2}CO_{3} | | Molec. Wt. 138 | | | | Potassium | Potassium carbonate| A strong solution is alkaline to iodide, KI | | test paper. Molec. Wt. 166 | | | Sulphates and | Same as for ammonia. | chlorides | | | | Potassium iodate | A pretty strong solution becomes | | yellow from liberation of iodine | | on addition of dilute sulphuric | | acid or, better, a strong solution | | of citric acid. | | Potassium | Similar to | See potassium iodide. bromide, KBr | potassium iodide | Molec. Wt. 119 | | | | Sodium carbonate, | Chlorides and | Same as for ammonia. Na_{2}CO_{3} | sulphates | Molec. Wt. 106 | | | | Sodium chloride, | Chloride of calcium | Oxalate of ammonium (after NaCl | Chloride of | addition of a little acetic acid) Molec. Wt. 58.5 | magnesium | gives a milkiness, or precipitate, | | indicating calcium; filter this | | out and add ammonia, chloride of | | ammonium, and phosphate of sodium | | (clear solutions). A precipitate | | indicates magnesium. Both the above | | cause dampness in wet weather. | | | Sodium sulphate | As for "sulphates" in ammonia. | | Potassium | Potassium carbonate | Effervescence with dilute acids, cyanide, KCN | nearly always | giving off a gas carbonic Molec. Wt. 65, | present | anhydride, which renders and hydrate, KHO | | lime-water turbid. Molec. Wt.