Monday, December 27, 2021

Preparation and standardization of 0.1 M sodium methoxide solution

Learn about the preparation and standardization of 0.1 M sodium methoxide solution through a laboratory experiment or practical.

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:


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.


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