I have to use 35% sodium carbonate solution to analyze tannin content according to Folin-Denis method. I tried to prepare the solution by dissolving 35 g of sodium carbonate into deionized water and make it up to 100 ml. But, the sodium carbonate did not fully dissolved even after heating. Can i filter it to get a clear solution using filter paper or got any other ways to prepare the solution? Thank you.
A standard solution is one whose concentration is known exactly. Standard solutions of liquids, for example acids, are easy to prepare and are usually supplied. Standard solutions of solids can be prepared by weighing a mass of solid, and dissolving it in a known volume of solution in a volumetric flask.Heat required amount of sodium carbonate (Na2CO3) to drive off water of crystallisation. Either: heat in an evaporating dish over a Bunsen burner for 30 minutes approx., or heat in a drying oven at about 110°C for 1 hour.
Agitate the solid periodically with a clean glass rod. Transfer to a desiccator after heating, and label it "sodium carbonate".
Solubility in water
Hi,below find the solubility of Sod carbonate in water.. Try this ..Temp has some effects on solubility. Hope this add some lights to ur query
Decahydrate:
7 g/100 mL (0 °C)
16.4 g/100 mL (15 °C)
34.07 g/100 mL (27.8 °C)
Heptahydrate:
48.69 g/100 mL (34.8 °C)
Monohydrate:
50.31 g/100 mL (29.9 °C)
48.1 g/100 mL (41.9 °C)
45.62 g/100 mL (60 °C)
43.6 g/100 mL (100 °C)
When you think um a certain concentration of a substance in a high concentration solution, you may first consult literature to check when it will dissolve. This way you tried but the substance had not dissolved. Since it can be dissolved below 40°C, may I suggest to check if your carbonate is really a sodium carbonate and not a calcium or other carbonate, because I had similar experience some days ago: a PA. quality calcium carbonate did not dissolve at 1 g per liter and has a pink colored residue. After that I changed the furnisher.
But ok, returning to your question, when you weight a mass of solid and complete the volume with water, you can not filter the solution because if there is a large quantity of solids removed by filtration, your solution has not the prepared concentration.
Are you using the decahydrate? The anhydrus should disolve completely....
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