11. TO DETERMINE THE SOLUBILITY OF THE GIVEN SOLUBLE SOLID AT THE LABORATORY TEMPERATURE.

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THEORY:

The solubility of a substance at a particular temperature is the amount of the substance in gm required to saturate 100 gm of water at that temperature.

Solubility= wt. of solute / wt. of solvent  x100

APPARATUS :

1) Beaker 100 ml

2) Porcelain basin

3) Desiccator

4) Air oven.

CHEMICALS:

1) Given soluble solid

PROCEDURE:

a) Take about 20 ml of distilled water in a clean small beaker. Add small quantities of the powdered solid a little at a time with constant stirring till it forms a saturated solution at room temperature (a solution in which some solid remains undissolved.)

b) Now, weigh a small porcelain basin.

c) Filter the solution into the porcelain basin, and carefully weigh the basin along with the solution.

d) Evaporate the solution to dryness on a water bath when the solid will be found left in the basin.

e) Dry the basin with the solid residue in an air oven, cool it in a desiccator and weigh again.

f) Repeat the process of heating in the air oven, cooling and weighing till the final weight is constant.

g) Note the laboratory temperature.

CALCULATIONS :

Weight of the empty basin = a gm

Weight of basin + saturated solution = b gm

Weight of basin + solid residue = c gm

Therefore, Weight of solid dissolved = (c- a) gm

and weight of water = (b – c) gm

Therefore,  Solubility of the given solid = (c – a) / (b – c)  x100