Standardization of Sodium Thiosulphate (Na2S2O3) solution with a Potassium Dichromate (K2Cr2O7) solution. DOCX

Title	Standardization of Sodium Thiosulphate (Na2S2O3) solution with a Potassium Dichromate (K2Cr2O7) solution.
Author	Meharaj Mahmmud
Pages	2
File Size	16.6 KB
File Type	DOCX
Total Downloads	57
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Description

Name of the Experiment: Standardization of Sodium Thiosulphate (Na2S2O3) solution with a Potassium Dichromate (K2Cr2O7) solution. Titration: A titration is a technique where a solution of known concentration is used to determine the concentration of an unknown solution. Apparatus: Conical flask, Burette, Retort stand. Dropper, Wash Bottle, Funnel, Ring Stand, Erlenmeyer Flask. Reagents: K2Cr2O7, HCl, KI, CeCl3, KCl, Na2S2O3. Preparation of standard Potassium Dichromate (K2Cr2O7) solution: Weigh out 1.47g of K2Cr2O7 in a 500mL volumetric flask. Add a small amount of distilled water and shake well to dissolve the solute. Make the solution up to the mark. Working procedure: 1. Take the supplied Na2S2O3 solution in the burette and note the initial reading. 2. Add 4mL of 10% KI solution in to conical flask. 3. Add 1g of NaHCO3 and shake to dissolve the salt. 4. Add 3mL of Conc. HCl slowly while gently rotating the flask to mix the liquid. 5. Add 10mL of K2Cr2O7 solution into the conical flask and mix the liquid. 6. Cover the flask immediately with a watch glass and allow the solution to stand for about 5 minutes in the dark (inside a desk, and color of the solution will be dark brown). 7. Titrate the liberated Iodine with the (Na2S2O3) from the burette until the color fades to turn pale yellow. 8. Now add 4 drops of Starch solution to it and the color of the solution changes to deep violet. 9. Continue the addition of Na2S2O3 from the burette until the color turns to light green or light blue. 10. Note the burette reading and this is the end point. 11. Repeat the steps 2 to 11 two more times and take the average of the volume of the Na2S2O3 solution. Experimental Data:...