Experiment No 1
AIM: To Prepare colloidal sol of abric gum.
Theory: Gum is composed of org. compounds It forms colloidal solution when dispersed in lukewarm water.
Requirements: Beaker, Glass road, funnel, tripod stand, Arabic gum.
Procedure:
Take 100 ml distilled water in 250 ml beaker and heat it to around 35oC to 45oC. Now take 5 gm of Arabic gum ( In powdered form) and make a past into lukewarm water slowly and along with constant stating with the help of glass road. Boil the contents for about 10 minutes again and then filter the above contents using filter paper. Filtrate obtained is a colloidal sol of Gum-Arabic.
Precautions: i) Use distilled water for the preparation of Gum sol.
(ii) Do not boil the contents or it may decompose.
Exp. No. 2
AIM : To prepare sol of starch.
Theory : Starch is a polymer of -(D)-Glucose. It forms colloidal sol when mixed with water. It is a macromolecular.
Apertures : Beaker, Glass rod, funnel, Filter paper, tripod stand, starch and distilled water.
Procedure : Mix about 500 mg of starch with few ml of distilled water make a paste of it. Transfer than distilled water in 250 ml beaker and heat it to boil the water.
Pour the paste of starch into boiling water slowly and along with constt string using glass rod. Now boil the mixture for about 10 minutes and then allow to cool at room temperature. Filter the contants using filter paper and this is colloidal sol of starch.
Precautions : i) Use distilled water for the preparation of starch sol.
ii) Boil the starch past into continuous stirring.
Exp. No. 3
AIM : To prepare colloidal sol of egg albumin.
Theory : Egg albumin is a protein and it forms colloidal sol when disappeared in water at room temperature. Colloidal sol of albumin is of lyophilic in nature.
Requirement : Beaker, glam rod, filter paper, distilled water, Common salt, egg.
Procedure: Break egg nell and transfer content is a beaker. Now decant slowly the colourless liquid into anoter beaker, which is egg albumin Now take 100 ml distilled water in 250 ml beaker and dissolve 5 gm of NaCl in it. add egg albumin into it. With constant string , filter the contents after 10-15 min. filtrate thus obtaind is colloidal sol of egg albumin.
Precaution : i) Yellow coloured yolk should not mix with colour liquid.
ii) Prepartion of egg albumin sol should be prepared at room temparture.
Ex. No. 4
AIM : To prepare colloidal sol of ferric hydroxide fe(OH)3.
Theory : Colloidal sol of ferric hydroxide is hydrophobic sol. It is prepared by the hydrolysis of ferric chloride using boiling water.
FeCl3 (aq) + 3H2O → Fe(OH)3 +3HCl
freshly prepared ferric hydroxide sol is positivaly charged due to adsorption of Fe+3 ions on the surface.
Requirement : Beaker, conical flask, glass rod, funnel, tripod stand, 2% aqueous solution of FeCl3, distilled water.
Procedure : Clear 250 ml conical flask by steaming process, and now add 100 ml of distilled in this cleaned conical flask and boil it by placing it on wire gauze stand. The burner flame. Now add 2% aqueous solution of FeCl3 drop wire into the boiling water, heat the contents to abstain deep red collour. Add distilled water to the conical flask to make up for the loss of water. Now keep the deep red colloidal sol at room temperature for some time. This is colloidal sol of ferric hydroxide.
Precautions : i) Addition of FeCl3 draperies to the boiling water.
ii) Add distilled water to make up for the loss water.
Ex. No. 5
AIM : To prepare colloidal sol of aluminum hydroxide Al(OH)3.
Theory : Aluminum hydroxide is hydrophobic is nature. It is obtained by hydrolysis of Al(OH)3 in boiling water.
AlCl3 + 3H2O → Al(OH)3 + 3HCl
Colloidal particles of Al(OH)3 are positively charged due to adsorption of Al+3 ions on the surface.
Requirement : 2% aqueous solution of AlCl3 , beaker, tripod stand, Beaker, conical flask, glass rod.
Procedure : The procedure is same as that of preparation of colloidal sol of ferric hydroxide.
Ex. No. 6
AIM : To prepare colloidal sol of arsenious sulphide (As2S3) is of lyophobic nature. It is obtained by passing H2S gas through aqueous solution of As2(OH)3
Following reaction takes place.
As2O3 + 3H2O → 2 As(OH)3
2As(OH)3 + 3H2S → As2S3 + 6H2O
As2O3 sol is negatively charged due to adsorption of S-2 ions on the surface.
Requirement : Round bottom flask, beaker, conical flask, glass rod, funnel, filter paper, burner, wire gauze, arsenious oxide and H2S gas, distilled water.
Procedure : Clean the conical flask by steaming process, and take 0.3 gm of As2O3 in conical flask mix it with 100 ml distilled water, boil the contents for about 10 minutes. Filter the solution, pass H2S gas through the filtrate, which thus yellow due to the formation of As2O3.
Precautions : i) As2O3 is a poisonous compound, so wash hands after experiment.
ii) Use steam cleaned conical flask.