Friday, April 29, 2022

Preparation and standardization of 0.1 M potassium iodate

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

Aim:

To prepare and standardize 0.1 M potassium iodate solution using 0.1 M solution of sodium thiosulphate.

Requirements:

Glasswares: Burette, burette stand, conical flask, volumetric pipette, beaker, volumetric flask, funnel, glass rod, wash bottle, etc.

Chemicals: AR grade potassium iodate (KIO3), potassium iodide (KI), sulphuric acid (H2SO4), sodium thiosulphate (Na2S2O3), starch, etc.

Apparatus: Digital/analytical balance, and Ultrasonicator.

Preparation of starch solution:

Click here to get the procedure.

Preparation of 0.1M potassium iodate solution:

Take 21.4 gm of previously dried potassium iodate in 500 ml of water. Once it has completely dissolved, make up the volume to 1000 ml.

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 25.00 ml of prepared solution of potassium iodate into 200 ml of water. In 20.00 ml of this solution, add 02.00 g of potassium iodide and 10.00 ml of 1M sulfuric acid.
  • Add 01.00 ml of the starch indicator.
  • Titrate the sample solution with 0.1M sodium thiosulphate until the endpoint is reached. The actual endpoint indicates by colorless to blue starch-iodine complex.
  • Properly record the readings of the burette.
  • To get accurate results, repeat the titration three times.
  • Take their mean and calculate the molarity of ferrous ammonium sulphate.
  • 01 ml of 0.1M sodium thiosulphate is equivalent to 0.003566 gm of KIO3.

Observation table:

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