Question

Explain how will you determine the solubility of NaNO₃ at room temperature.

Answer 1

To determine the solubility of NaNO₃(Sodium nitrate) at room temperature:

• In order to check its solubility first grind the NaNO₃ and dissolve it in 100cm³ of water, stirring it well.
• Keep on dissolving more sodium nitrate into the solution until the NaNO₃ stops dissolving in it, so that the solution will become saturated.
• Using the thermometer record the temperature of the solution.
• Weigh an empty and clean china dish.
• In an empty china dish, 50 cm³ of a saturated solution is poured.
• Now weigh the china dish again.
• Place the china dish over the sand bath in order to heat.
• Stir the solution placed on the sand bath.
• Heating of solution is stopped when solid residue is obtained.
• The obtained solid residue crystals are allowed to cool at room temperature.
• To dry the crystal place the crystals in the desiccator containing anhydrous CaCl₂.
• Calculation of solubility of NaNO₃.
• Weight of empty china dish=W_n
• Weight of empty china dish+NaNO₃ saturated solution=W_m
• Weight of empty china dish+ crystals of NaNO₃ = W_o
• Observed temperature of NaNO₃ saturated solution=t^oC
• Saturated solution weight = W_m-W_n
• Weight of the crystals of NaNO₃ =W_o-W_n
• Weight of water present in saturated solution= (W_m-W_n)-(W_o-W_n)g
• Solubility of NaNO₃ =$\frac{Soluteweight}{Solventweight}X100$
• Solubility of NaNO₃ =$\frac{W_o-W_n}{W_m-W_o}X100g/100gofwaterat{t}^{o}C$