Synthetic Inorganic Chemistry

FILTERING; COLLECTING PRECIPITATES 5

3. TRANSFERRING PRECIPITATES OR CRYSTALS
   If large crystals have separated from a liquid they may be picked
   out, or the liquid may be poured off.
   If a precipitate or a crystalline meal has formed it must be
   drained in a filter funnel. First pour off the liquid (see Note 2) —
   through the filter if necessary, so as to save any floating particles
   of the solid — then pour the main part of the damp solid into the
   filter. A considerable part, of the solid will adhere to the dish;

FIG. l FIG. 2

most of this may be scraped out by means of a spatula, but the
last of it is most easily rinsed into the filter. For rinsing, a jet of
water from the wash bottle (Fig. 2) may be used if the solid is very
insoluble. If the solid is soluble in water, some of the saturated
solution may be poured back into the dish from out of the filter
bottle, and by means of this the last of the solid may be removed
to the filter.

4. FILTERING; COLLECTING PRECIPITATES
   (a) A coarse-grained crystal meal can best be collected in a filter
   funnel in which a perforated porcelain plate is placed, and the
   mother liquor clinging to the crystals can best be removed with
   the aid of suction (see next paragraph).