Question

What is a possible procedure I can use to determine the direct solubility of KHT following these guidelines?

1. Based on the principle of making a saturated solution, KHT is added until excess solid is formed. The room temperature needs to be recorded and kept to avoid solubility being changed by temperature duing preparation.

2. The excess KHT solid should be filtered.

3. Method of titration using a standard soltuion of NaOH.

4. Finally, how will you test the temperature effect on solubility of KHT?

Answer 1

(1) Approximately measure 100 mL of water. To this you keep on adding KHT until no more KHT can be dissolved more. This can be observed by formation of a solid. Record the room temperature in your notebook.

(2) Now filter the excess KHT. You can use buchner funnel and whatmann filter paper for this purpose.

(3) Now Pipette out 25 mL of the aqueous solution of KHT into a volumetric flask, add suitable indicator and then titrate the solution with standard NaOH solution. Record the volume of NaOH required for the titration from burette. Then use the following formula to calculate the molarity (solubility) of KHT

(4) Now repeat the entire procedure (from (1) to (3)) by heating the solutions to a different temperature, say 10 deg C above room temperature. You can plan the same by carrying out first set of experiments in the early morning and second set of experiments in the mid afternoon. There will be significant difference in the room temperature. At two different temperatures, you will get different solubilities. This way you can test the temperature effect on solubility of KHT.