| | 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. 56 | | Kaolin | Chalk | Effervescence with dilute acids. | | Water, | Sulphates and | Same as for ammonia.  H_{2}O | chlorides | Molec.  Wt. 18 | | | Calcium carbonate, | Deposited by boiling.  Test as | temporary hardness | for calcium chloride.  See | | sodium chloride. | | | Ammonia, almost | Brown coloration, or | always present in | precipitate with Nessler’s | distilled and rain | reagent. | water | | | Gelatine | Alum | Ash, sometimes as much as ten | | per cent. | | | Fatty matter | Separated by precipitation with | | alcohol.  Dissolved out by ether | | or benzine, and left as a residue | | on evaporation of the solvent. | | | | Ammonium bromide | Potassium bro- | Leaves a residue when heated.  (NH_{4})Br | mide or other | Molec.  Wt. 98 | non-volatile | | bodies | | | | Ammonium chloride | Same as for chlorides in | | ammonia. | | Pyrogallic acid | Powdered glass | Left behind on solution. | | Potassium iodide | Potassium bromide | The crystals of bromide are | | usually more transparent than