Learn the identification tests of sodium bicarbonate through a laboratory experiment or practical.
Aim:
To perform identification tests of sodium bicarbonate on a given sample.
Reference: Indian Pharmacopoeia (IP) 2010
Requirements:
Glasswares and miscellaneous:
Test tube, measuring cylinder, pipette, glass rod, volumetric flask, beaker, dropper, rubber stopper, test tube stand, test tube holder, litmus paper, and balance, etc.
Chemicals:
Sodium bicarbonate (NaHCO3), magnesium sulphate (MgSO4), calcium chloride (CaCl2), barium hydroxide (Ba (OH)2), phenolphthalein solution, hydrochloric acid (HCL), potassium carbonate (K2CO3), potassium hydroxide (KOH), and potassium antimonate (K[Sb(OH)6]), etc.
Preparation of reagents:
3% barium hydroxide solution preparation:
Take 03.00 gm of barium hydroxide and dissolve to 100.00 ml of distilled water in a volumetric flask, and properly mix it.
2 M acetic acid preparation:
Take 11.40 ml of glacial acetic acid using a pipette and dissolve to 100.00 ml of distilled water in a volumetric flask, and properly mix it.
1% w/v phenolphthalein solution preparation:
Take 0.1 gm of phenolphthalein and dissolve to 100.00 ml of 95% ethanol in a volumetric flask, and properly mix it.
15% potassium carbonate solution preparation:
Accurately weigh 15.00 g of K2CO3 and pour in 100.00 ml of distilled water and properly mix it.
5 % w/v potassium hydroxide preparation:
Accurately weigh 05.00 g of KOH and pour in 100.00 ml of distilled water and properly mix it.
Dilute HCL preparation:
Click here to get the procedure.
1M NaOH solution preparation:
Take 04.00 gm of sodium hydroxide and dissolve in 70.00 ml of distilled in a volumetric flask and properly mix it. Once it has completely dissolved and cooled, make up the volume to 100 ml.
Potassium antimonate solution preparation:
Take 02.00 gm of potassium antimonate pour into 95.00 ml of water and boil it until dissolved. Cool quickly; add 50.00 ml of prepared KOH solution and 05.00 ml of 1M NaOH solution. Let stand for 24 hours, filter it, and then add enough water to produce 150.00 ml.
Procedure for identification of sodium bicarbonate:
- Test 1: When a solution of a given chemical is boiling, carbon dioxide is released, turning moist blue litmus paper red.
- Test 2: When a substance solution is treated with a magnesium sulphate solution, no precipitate is produced. Boil; A white precipitate is formed.
- Test 3: Take 0.1 gm of sample to be tested in the test tube and add 02 ml of water. Then add 02 ml 2 M acetic acid, immediately close the tube with a stopper equipped with a glass tube bent at two right angles, gradually heat, and collect the gas in 05 ml barium hydroxide solution. A white precipitate is formed which dissolves on the addition of additional dilute HCL.
- Test 4: Add 0.1 ml of phenolphthalein solution to 05 ml of a 5 % w/v solution, a light pink color obtains. When the solution is heated, a gas is evolved, and the solution turns red.
- Test 5: Add 02 ml of a 15 % w/v potassium carbonate solution to 02 ml of a 5 % w/v sodium bicarbonate solution and heat to boiling; no precipitate forms. Add 04 ml of freshly prepared solution of potassium antimonate and heat to boiling. Allow it to cool in ice, then scrape the interior of the test tube with a glass rod if required; a dense, white precipitate will develop.
Observations:
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Identification Test |
Observation |
Inference |
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Test 1 |
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Test 2 |
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Test 3 |
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Test 4 |
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Test 5 |
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Results:
The given sample complies with the tests 1 / 2 / 3 / 4 / 5 and does not comply with the tests 1 / 2 / 3 / 4/ 5 for the identification of sodium bicarbonate as per IP 2010.
It suggests that the given sample is of ………………………...
