Prepare colloidal solution of starch and ferric hydrochloride separately
Answers
Aim:
The aim of this experiment – to prepare ferric hydroxide sol.
Theory:
Ferric hydroxide (Fe(OH)3) can form a lyophobic sol. Sulfides or metal hydroxides in which colloidal solution, when treated with water, are termed as lyophobic colloids. Fe(OH)3 sol is obtained by hydrolysis of ferric chloride with boiling distilled water. The reaction is as follows:
FeCl3(aq) + 3H2O(l)→boil Fe(OH)3(s) +3HCl(aq)
The hydrochloric acid formed during the hydrolysis destabilizes the ferric hydroxide sol and therefore must be removed through the process of dialysis.
Materials required:
The apparatus and materials required for this experiment are as follows:
Glass rod
Round bottom flask
Boiling tube
Conical flask of 250 mL volume
Tripod stand
Funnel
Beaker of 250 mL volume
Burette
Wire gauze
Dropper
Burner
Wire gauze
Iron stand with clamp
Boiling tube
Distilled water
The solution of ferric chloride
Procedure:
1. Take a conical flask of volume 250 mL and steam clean it.
2. To clean the conical flask by steaming out process take the help of the figure given below.
Experimental Setup:
Steaming out the process for cleaning conical flask
3. Prepare a 2% solution of ferric chloride by taking 2 g of pure ferric chloride in 100mL of distilled water.
4. Take the conical flask cleaned by steaming out process and add 100mL of distilled water.
5. Boil the water on a wire gauze.
6. Drop by drop pour 10 mL of ferric chloride solution with the help of a dropper or burette.
7. Constantly keep stirring the boiling water mixture while adding ferric chloride solution.
8. Heat the conical flask containing a mixture of distilled water and ferric chloride solution until you see a brown or deep red colored ferric hydroxide solution.
9. Allow the mixture in the conical flask to settle at room temperature.
10. Label the flask containing the mixture as ferric hydroxide sol.
Precautions to be taken during the experiment:
Fe(OH)3 sol gets affected due to the presence of impurities. Therefore, to avoid this conical flask is cleaned by steaming out process.
The FeCl3 solution is added dropwise.
Heat the mixture of distilled water and ferric chloride solution until brown or deep red color is obtained.
The hydrochloric acid (HCl) formed is removed by the process of dialysis to avoid destabilization of sol.
Viva Voce:
1. How to prepare 2% of ferric chloride solution?
Ans: Mix 2 g of ferric chloride in 100 mL of distilled water.
2. Why is it important to clean the apparatus by steaming out the process?
Ans: Ferric hydroxide sol gets affected due to the presence of impurities. Hence, the apparatus is steam cleaned before the experiment.
3. Boil the mixture of ferric chloride solution and distilled water until it attains _______ or _______ color.
Ans: Deep red or brown color.
4. Hydrolysis of ferric chloride results in ________.
Ans: Formation of hydrochloric acid.
5. What is the quantity of ferric chloride solution added to 100 mL boiling distilled water?
Ans: 10 mL.