The salt can be recovered from the filtrate by evaporation of the water.
The filtrate was evaporated and the residue extracted with alcohol.
When, therefore, chromium is not detected in the precipitate, the filtrate should also be examined.
If turmeric is present the filtrate will appear fluorescent.
In the filtrate the free alkali is estimated by a normal acid.
If gold is present, it will now be held in solution in the filtrate.
The liquid is poured on a small dry filter and washed with warm benzoline, the filtrate being collected in a small wide beaker.
Filter and evaporate the filtrate until the fumes of sulphuric acid begin to be evolved, when 10 gr.
We then filter, and add to the filtrate carbonate of potash or soda, until there is no further precipitation of carbonate of lime.
The filtrate can then be subjected to Marsh's or Reinsch's process.