Friday, March 10, 2023
Acetic acid in non aqueous titration
Friday, March 3, 2023
Why water is not used in non aqueous titration
Why water is not used in non-aqueous titration?
What should be avoided in non-aqueous titration?
Which titration does not contain water as a solvent?
Which indicator is used in non-aqueous titration?
Thursday, March 2, 2023
Factors affecting non aqueous titration
Factors that affect non-aqueous titration:
- Temperature: The volume of non-aqueous solutions used is affected by temperature, which causes the concentration of the sample to fluctuate. Temperature affects non-aqueous solvents because they expand more than water.
- Highly acidic or basic condition: In the process of titrating weak bases or acids, the addition of very acidic or basic solvents raises the level of acidity or basicity, which increases the consumption of titrant.
- Moisture level: When doing non-aqueous titrations, it is important to stay away from moisture in order to neutralize the solution and make the endpoint more accurate.
- Acid-base characteristics of the solvents used: In a non-aqueous titration, the end-point is affected by the acid-base characteristics of the solvents used.
- Protolysis of the substance: The endpoint of the reaction may increase due to the protolysis of the substance.
- Dielectric constant: Solvents with low dielectric constants are often used in non-aqueous titrations, which produce sharp endpoints.
- Carbon dioxide: The endpoint of acid-base titrations can be affected when carbon dioxide (CO2) from the air dissolves in water and forms carbonic acid, so it should be controlled.
Monday, February 27, 2023
Applications of non-aqueous titration
- Suitable for titrations of weak acid and base
- An appropriate solvent medium is used to dissolve organic compounds
- Aprotic solvents-(Chloroform and benzene)
- Protophilic solvents-(Acetic and acid sulphuric acid)
- Protogenic solvents-(Amines liquid and ammonia)
- Amphiprotic solvents-(Acetic acid and alcohols)
Applications of non-aqueous titration:
- Non-aqueous titration has a wide range of applications, especially in the field of medicine. Some applications of non-aqueous titration are mentioned below.
- Assay and composition analysis of pharmaceutical products is one of the most important applications of non-aqueous titration.
- It is used to know the purity of assays.
- It is employed to determine the concentration expressions.
- A mixture of primary, secondary, and tertiary amines is determined using a non-aqueous titration method.
- Non-aqueous titrations are used to measure the concentration of a certain analyte.
- Non-aqueous titrations can be used to determine the identity of hydrophobic drugs such as diuretics, phenobarbitone, tetracyclines, and steroids, etc,
- It is also used to determine the composition of antitubercular drugs and adrenergic drugs.
Monday, December 27, 2021
Preparation and standardization of 0.1 M sodium methoxide solution
Aim:
To prepare and standardize 0.1M sodium methoxide solution using benzoic acid as a primary standard. (Non-aqueous titration)Requirements:
Glasswares: Burette, burette stand, conical flask, volumetric pipette, beaker, volumetric flask, funnel, glass rod, and wash bottle, etc.Chemicals: Sodium methoxide (CH3NaO), benzoic acid (C7H6O2), thymolphthalein indicator, dimethylformamide (C3H7NO), and methanol (CH3OH), etc.
Titration procedure:
- All glassware should be cleaned and dried according to standard laboratory procedures.
- Before filling the burette for the titration, rinse it with distilled water and then pre-rinse it with a portion of the titrant solution. Pre-rinsing is required to make sure that all solution in the burette is the desired solution, not a contaminated or diluted solution.
- Take the unknown stock solution of titrant in a clean and dry beaker then fill the burette using the funnel.
- Remove air bubbles from the burette and adjust the reading to zero.
- Take 0.4 gm of benzoic acid, properly weighed, and dissolved in 80.00 ml of dimethylformamide.
- Add 0.15 ml of thymolphthalein indicator solution.
- Perform the titration with sodium methoxide solution until the end-point.
- The blue color indicates the blue endpoint of the titration.
- Make any necessary corrections after performing a blank determination.
- During the titration, protect the solution from atmospheric carbon dioxide
- To get accurate results, repeat the titration three times.
- Properly record the readings of the burette.
- Take their mean and calculate the molarity of the sodium methoxide solution.
Observation table:
|
Sr.
No. |
Content
in conical flask |
Burette
reading |
Volume
of titrant used (ml) |
|
|
Initial |
Final |
|||
|
1 |
|
|
|
|
|
2 |
|
|
|
|
|
3 |
|
|
|
|
|
|
Mean: |
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Calculations:
1 ml of 0.1 M sodium methoxide is equivalent to 0.01221 g of C7H6O2.M= weight of C7H6O2 / 0.01221 x volume of titer (ml) x 12.21
Result:
The strength of the prepared sodium methoxide solution was found to be_____M.Sunday, December 26, 2021
Preparation and standardization of 0.1 M tetrabutylammonium hydroxide solution
Aim:
Requirements:
Preparation of 0.1 M tetrabutylammonium hydroxide solution:
- Take 40.00 g of tetrabutylammonium iodide, pour into a glass flask and add 90.00 ml of methanol (dehydrated) to dissolve.
- Put it in an ice bath, add 20.00 g of silver oxide (powdered), close the lid, and agitate vigorously for 1 hour.
- Test the supernatant liquid for iodides after centrifuging a few ml. (To test for iodides: add 00.50 ml of mercuric chloride solution to 01.00 ml of this solution; if a dark red precipitate forms, the test is positive for iodide).
- If the test is positive, add another 02.00 gm of silver oxide and let it stand for another 30 minutes with intermittent agitation.
- Once all the iodide has reacted, filter it through a fine sintered-glass filter.
- Rinse the flask and filter with three volumes of toluene (anhydrous), 50.00 ml each.
- Add the filtrate washings and dilute with toluene to 1000 ml.
- For 10 minutes, flush the solution with dry, carbon dioxide-free nitrogen.
- Store it in an airtight container away from carbon dioxide and moisture and use it for up to 60 days.
Titration procedure:
- All glassware should be cleaned and dried according to standard laboratory procedures.
- Before filling the burette for the titration, rinse it with distilled water and then pre-rinse it with a portion of the titrant solution. Pre-rinsing is required to make sure that all solution in the burette is the desired solution, not a contaminated or diluted solution.
- Take the unknown stock solution of titrant in a clean and dry beaker then fill the burette using the funnel.
- Remove air bubbles from the burette and adjust the reading to zero.
- Take 0.4 gm of benzoic acid, properly weighed, and dissolved in 80.00 ml of dimethylformamide.
- Add a few drops of a 1 % w/v solution of thymol blue.
- Perform the titration with tetrabutylammonium hydroxide solution until the end-point.
- The blue color indicates the blue endpoint of the titration.
- Make any necessary corrections after performing a blank determination.
- During the titration, protect the solution from atmospheric carbon dioxide
- To get accurate results, repeat the titration three times.
- Properly record the readings of the burette.
- Take their mean and calculate the molarity of the tetrabutylammonium hydroxide solution.
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:
Result:
What is the molecular mass of c16h37no?
Which indicator is used in the standardization of 0.1 M tetrabutylammonium hydroxide?
Saturday, August 28, 2021
Assay of sodium benzoate
Aim:
Requirements:
Principle of assay of sodium benzoate:
Preparation and standardization of 0.1 M perchloric acid:
Preparation of 1-naphtholbenzein indicator solution:
Titration procedure:
- All glassware should be cleaned and dried according to standard laboratory procedures.
- Before filling the burette for the titration, rinse it with distilled water and then pre-rinse it with a portion of the titrant solution. Pre-rinsing is required to make sure that all solution in the burette is the desired solution, not a contaminated or diluted solution.
- Note: Since it is a non-aqueous titration, it needs to be extra careful during the cleaning and drying of glassware. Glassware is required to be clean with acetone and dried for purpose.
- Take the unknown stock solution of titrant in a clean and dry beaker then fill the burette using the funnel.
- Remove air bubbles from the burette and adjust the reading to zero.
- Take 0.25 gm of sodium benzoate and pour it into a conical flask.
- Add 20.00 ml anhydrous glacial acetic acid, sonicate to dissolve, and if required warm it at 50°C.
- Then add 2 drops of 1-naphtholbenzein indicator solution.
- Titrate the sample solution with the perchloric acid solution until the endpoint is reached.
- The actual endpoint of the titration is indicated by a change of violet color to emerald green.
- To get accurate results, repeat the titration three times.
- Properly record the readings of the burette.
- Take their mean and calculate the percentage purity of sodium benzoate.
- For the blank determination, repeat the titration as directed above but without the sodium benzoate (B).
A. For
titration of sample
|
Sr. No. |
Content
in conical flask |
Burette
reading |
Volume
of titrant used (ml) |
|
|
Initial |
Final |
|||
|
1 |
|
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|
|
2 |
|
|
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|
3 |
|
|
|
|
|
Mean: |
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B. For
titration of blank
|
Sr. No. |
Content
in conical flask |
Burette
reading |
Volume
of titrant used (ml) |
|
|
Initial |
Final |
|||
|
1 |
|
|
|
|
Calculations:
Result:
Preparation and standardization of 0.1M perchloric acid
Aim:
Requirements:
Principle:
Preparation of crystal violet indicator solution:
Preparation of 0.1 M perchloric acid:
Titration procedure:
- All glassware should be cleaned and dried according to standard laboratory procedures.
- Before filling the burette for the titration, rinse it with distilled water and then pre-rinse it with a portion of the titrant solution. Pre-rinsing is required to make sure that all solution in the burette is the desired solution, not a contaminated or diluted solution.
- Note: Since it is a non-aqueous titration, it needs to be extra careful during the cleaning and drying of glassware. Glassware is required to be clean with acetone and dried for purpose.
- Take the unknown stock solution of titrant in a clean and dry beaker then fill the burette using the funnel.
- Remove air bubbles from the burette and adjust the reading to zero.
- Take 0.35 gm of previously heated (120°C for 2 hours) KHP and pour it into a conical flask.
- Add 50.00 ml anhydrous glacial acetic acid.
- Then add 2 drops of crystal violet indicator solution
- Titrate the sample solution with the perchloric acid solution until the endpoint is reached.
- The actual endpoint of the titration is indicated by a change of violet color to emerald green.
- To get accurate results, repeat the titration three times.
- Properly record the readings of the burette.
- Take their mean and calculate the molarity of a perchloric acid solution.
- For the blank determination, repeat the titration as directed above but without the potassium hydrogen phthalate (B).
Observation table:
A. For titration of sample
|
Sr. No. |
Content
in conical flask |
Burette
reading |
Volume
of titrant used (ml) |
|
|
Initial |
Final |
|||
|
1 |
|
|
|
|
|
2 |
|
|
|
|
|
3 |
|
|
|
|
|
Mean: |
|||
B. For titration of blank
|
Sr. No. |
Content
in conical flask |
Burette
reading |
Volume
of titrant used (ml) |
|
|
Initial |
Final |
|||
|
1 |
|
|
|
|
