To prepare Potash alum from scrap aluminum.

Experiment – 15

Class – XII

Subject – Chemistry

 

Aim:-

To prepare Potash alum from scrap aluminum.

Apparatus:-

250 ml Flask, Funnel, Beaker, Scrap Aluminum, or cola can or aluminum foil.

Chemicals required:

Potassium aluminum hydroxide solution (KOH), 6 mole Sulphuric acid (H₂So₄), ethanol.

Theory:

Aluminum metal is treated with hot aqueous KOH solution, Aluminum dissolves as potassium aluminate KAl (OH)₄. Salt.

2 Al + 2 KOH + 6 H₂O    à    2 KAl (OH)₄ + 3 H₂

Potassium aluminate solution on treatment with hot dil. Sulphuric acid give precipitate Al (OH)₃ which dissolves on addition of small excess of H₂So₄ & heating.

2 KOH + H₂So₄    à   2 Al (OH)₃ + K₂So₄ + 2 H₂O

2 Al (OH)₃ + 3 H₂So₄     à Al₂ (So₄) + 6 H₂O

The resulting solution is concentrated to near saturation and cooled on cooling crystals of potash alum crystalize out.

K₂So₄ + Al₂ (So₄)₃ + 24 H₂O     à     K₂ So₄ Al₂ (So₄)₃ + 24 H₂O (S)

Procedure:

1.    A small piece of Aluminum was clean with steel wool & out it into small piece.

2.    About 1 g of aluminum put it into the solution of 50 ml of 4 KOH in conical flask and dissolved in the aluminum.

3.    In order to facilate the solution flask heated gently.

4.    Continue heating until all aluminum reacts.

5.    Then filter the solution to remove insoluble impurity & volume of solution is reduced about 25 ml by heating.

6.    The filtrate was allow to cool. 6 K₂So₄ is added in the solution slowly.

7.    Then resulting solution is cooled in an ice bath.

8.    The solution is filtered using vacuum.

Observation:

Mass of aluminum metal      -        2.39 g

Mass of potash alum.            -        4.67 g

Theoretical yield of potash alum   -        5.43 g

 

Result:

Potash alum of 86% yield was prepared from scrap aluminum.

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15.	To detect the presence of Carbohydrate, Protein, Starch in given compound A, B, & C.	Click Here
16.	To prepare Potash alum from Scrap Aluminum.	Click Here