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Preparation and Standardization of Various Molar and Normal Solution

Preparation and Standardization of 0.1 N NaOH
Solution

Preparation of 0.1 N NaOH Solution.

Dissolve 4.1gm of sodium Hydroxide ‘pallets’ in water to make up to 1000 ml. a volumetric flask.

Standardization of 0.1 N NaOH Solution

Weigh 0.2gm of potassium hydrogen phthalate (PHP), which previously dried at 120^oC for four hours, in a conical flask

Dissolve it with distilled water.

Add 2-3 drops of phenolphthalein indicator and titrate with NaOH. Solution.

Wt of PHP (mg)

Normality= ——————————————

Vol. of NaOH used x 204.22

Preparation and Standardization of 0.1N Perchloric acid Solution.

Preparation of 0.1N Perchloric acid Solution.

Mix 8.5 ml. of Perchloric acid with 500 ml. of Glacial acetic and 21 ml. of acetic anhydride, cool and Glacial acetic acid to make 1000ml.

Alternatively mix 11ml of 60% Perchloric acid with 500ml of Glacial acetic and 30ml acetic anhydride, cool and add Glacial acetic acid to make 1000ml.

Allow the solution to stand for one day for the excess acetic anhydride to be combined.

Carry out determination of water. If water content is more than 0.05%,add more acetic anhydride.

If solution contains no water. Add sufficient water to obtain content between 0.02 to 0.05%.

Standardization of 0.1N Perchloric acid Solution.

Weigh 0.2gm of potassium hydrogen phthalate (PHP), which previously dried at 120^oC for four hours, in a dry conical flask

Dissolve it with anhydrous Glacial acetic acid.

Add 2-3 drops of crystal violet indicator and titrate with Perchloric acid solution.

Normality = __ __ Wt. of PHP (mg.) ____

Vol. of Perchloric acid used x 204.22

Preparation and Standardization of 0.1 N Sodium Nitrite Solution.

Preparation of 0.1 N Sodium Nitrite Solution.

Dissolve 25gm of sodium thiosulphate and 0.2gm of sodium carbonate in carbon-dioxide-free water and dilute to 1000 ml with the same solvent.

Standardization of 0.1 N Sodium Nitrite Solution.

Weigh 0.2 gm of sulphunilic acid in conical flask.

Dissolve it with distilled water if necessary warm and cool,

Add 3gm. of potassium bromide and carry out nitrite titration.

Normality = ____Wtof sulphnilic acid (mg) ____

Vol. of Sodium Nitrite used x 173.19

Preparation and Standardization of 0.05 M Disodium EDTA Solution

Preparation of 0.05 M Disodium EDTA Solution

Dissolve 18.62gm. of di-sodium acetate in sufficient water to produce 1000ml.

Standardization of 0.05 M Disodium EDTA Solution

Weigh accurately 0.1 gm of magnesium sulphate in a conical flask

Dissolve it with distilled water

Add 10.0ml. ammonia- ammonium buffer pH-10.0, erichrom black-T indicter and titrate with EDTA solution.

Normality= ____Wt of Magnesium Sulphate (mg) ____

Vol. of EDTA Solution used X 246.47

Preparation and Standardization of 0.1 N Iodine Solution

Preparation of 0.1 N Iodine Solution

Dissolve about 14 gm of iodine in solution of 35 gm. potassium iodine in 100 ml. of water,

Add three drops of hydrochloric acid

Dilute with water to 1000ml.

Standardization of 0.1 N Iodine Solution

Weigh accurately 40.0 mg. of Arsenic trioxide (which previously dried at 105⁰C for 2 hours) in a conical flask

Add 10ml 1.0 M NaOH solution,

Add 25ml distilled water

Add 3-4drops methyl red indicator

Neutralized with 1.0 N Hcl solution

Add 3gm. of sodium carbonate

Add 3-4 ml of starch indicator and titrate with Iodine

solution.

Normality= ____Wt of Arsenic trioxide (mg) ____

Vol. of Iodine Solution used x 246.47

Preparation and Standardization of 0.1 N Sodium thiosulphate.

Preparation of 0.1 N Sodium thiosulphate.

Dissolve about 26 gm. of sodium thiosulphate and 0.2 gm of sodium carbonate in 1000ml of water.

Standardization of 0.1 N Sodium thiosulphate.

Weigh accurately about 100 gm of potassium iodide and dissolve in 50ml of water.

Add 2Gm of potassium iodide and 10ml of 1N hydrochloric acid

Titrate with the sodium thiosulphate solution using starch solution added towards the end of the titration.

End point reached when blue colour is discharged.

Wt of KIO₃ (mg.)

Normality = ————————————–

Vol. of Na₂S₂O₃ used X 35.67

Preparation and Standardization of 0.1 N Potassium permanganate.

Preparation of 0.1 N Potassium permanganate.

Weigh 15.8 gm. of potassium permanganate in 1000ml. volumetric flask and dilute to 400 ml of distilled water,

Heat on a water bath for one hour and allow to cool and make up the volume up to 1000ml with distilled water,

Allow to stand for two days and filter through the Glass wool.

Standardization of 0.1 N Potassium permanganate

Take 25ml of the potassium permanganate solution in stoppered conical flask

Add 2gm. of potassium iodide, followed by 10ml 1M H₂SO₄solution.

Titrate the librated iodine with 0.1M sodium thiosulphate, using 3ml. Of starch indicator added towards

The end of the titration. Perform a blank-determination and make any necessary correction.

25 X Normality KMnO₄= volume of sodium thiosulphate used x Normality of sodium thiosulphate

Applications of Molar and Normal Solutions

Molar and normal solutions have a wide range of applications, including:

Analytical Chemistry: They are used in quantitative chemical analyses to determine the concentration of unknown substances.
Medical Laboratories: Molar and normal solutions are used in clinical laboratories for various diagnostic tests.
Industrial Processes: These solutions are crucial in industries like pharmaceuticals and food processing for quality control and production processes.

Frequently Asked Questions (FAQs)

What is the difference between molar and normal solutions?
Molar solutions express concentration in moles per liter (M), while normal solutions express the equivalent weight in grams per liter (N).
Why is standardization important for these solutions?
Standardization ensures that the prepared solutions have accurate and known concentrations, crucial for precise chemical analyses.
What is a primary standard in standardization?
A primary standard is a pure and stable compound that can be used to prepare a known molar solution for titration.
What are some common mistakes to avoid when preparing molar and normal solutions?
Avoid errors in weighing the solute, ensure complete dissolution, and accurately measure the final volume to prevent concentration discrepancies.
What are some safety precautions when working with these solutions in a laboratory?
Wear appropriate safety gear, work in a well-ventilated area, and follow laboratory safety protocols to prevent exposure to chemicals.