Learn about the preparation and standardization of sulphuric acid (1M) using sodium carbonate as the primary standard and methyl orange as an indicator.
Aim:
To prepare and standardize 1M sulphuric acid using primary sodium carbonate.
Principle:
The principle of sulphuric acid standardization is an example of alkalimetry. When a strong acid is titrated with a strong base, the salt formed in the reaction is not hydrolyzed, so the pH of the final solution is not 07.00 at the endpoint of the reaction. Standardize H2SO4 solution (a strong acid) by titration with Na2CO3 solution (a strong base) by using methyl orange as an indicator. When sodium carbonate is titrated with sulphuric acid, the following reaction occurs.
The molecular weight of sulphuric acid (H2SO4) is 98.07 g/mol.
How to prepare 1M sulphuric acid solution:
Take 54.00 ml of sulphuric acid (H2SO4) and dissolve in 500 ml of distilled water in a volumetric flask, and properly mixing it. Allow to cool at ambient temperature, make up the volume to 1000 ml.
How to prepare sodium carbonate solution (1M):
Take 286.15 gm of Na2CO3and dissolve in 500 ml of distilled water in a volumetric flask, and properly mixing it. Once it has completely dissolved, make up the volume to 1000 ml.
Procedure for standardization of 1M H2SO4:
In a clean conical flask, pipette out exactly 10.00 ml of 1M Na2CO3 solution and 2 to 3 drops of methyl orange indicator. Titrate the solution contents in the flask with sulphuric acid until the endpoint. The actual endpoint of the titration is indicated by a red color. To get accurate results, repeat the titration three times. Note down the burette reading in the observation table.
Observation table:
|
Sr. No. |
Content
in conical flask |
Burette
reading |
Volume
of titrant used (ml) |
|
|
Initial |
Final |
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|
1 |
|
|
|
|
|
2 |
|
|
|
|
|
3 |
|
|
|
|
|
Mean: |
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Calculations:
M1V1=M2V2
Where,
V1 = Volume of 1M Na2CO3 solution = 10 ml
M1 = Molarity of Na2CO3 solution = 1M
V2 = Volume of H2SO4 solution rundown
M2 = Molarity of H2SO4 =?
Therefore,
M2 = M1V1 / V2
Result:
The strength of the prepared sulphuric acid was found to be_____M.
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