.Chemistry Investigatory Project..

CHEMISTRY
INVESTIGATORY PROJECT
EXTRACTION OF
POTASH ALUM
Submitted by-
Geetali
XII-A
R. no 7
SNBP INTERNATIONAL SCHOOL, RAHATANI
CERTIFICATE
This is to certify that Geetali Ulhas Madkaiker, student of class XII-A has successfully
completed the Chemistry Investigatory project under the guidance of Mrs. Reenu during
the year 2019-20 in the partial fulfillment of practical examination
conducted by AISSCE, New Delhi.
Date: School stamp Principal’s Signature
Signature of external examiner Signature of subject teacher

ACKNOWLEDMENTS:
I would like to express my special thanks and
gratitude to my Chemistry teacher Mrs. Reenu
Sharma, as well as our principal Mrs. Jayshree
Venkatraman, who gave me the golden
opportunity to do this wonderful project on the
topic “Extraction of Potash Alum”, which also
helped me in doing a lot of Research and I came
to know about so many new things I am really
thankful to them.
Secondly, I would also like to thank my parents
and friends who helped me a lot in finalizing
and compiling this project within the limited
time frame.
 CONTENTS:
1. AIM
2. INTRODUCTION
3. THEORY
4. MATERIALS REQUIRES
5. PROCEDURE
6. OBSERVATIONS
7. CONCLUSION AND ANALYSIS
8. PRECAUTIONS
9. BIBLIOGRAPHY
 AIM:
To prepare potash alum from scrap aluminum
 INTRODUCTION:
o Aluminum:
 Aluminum is a metal with low density, high tensile strength and
high resistance to corrosion.
 It is a good conductor of electricity
 These properties make aluminum an ideal metal for the
manufacture of airplanes, automobiles, lawn furniture, utensils,
aluminum cans as well as for power lines.
o Recycling of Aluminum:
 The recycling of aluminum cans and other aluminum products is a
very positive contribution to save our natural resources.
 Most of the recycled aluminum is melted and recast into other
aluminum metal products or used in the production of various
aluminum compounds, the most common of which are the alums.
Alums are double sulphates having the general formula:
X2SO4.M2(SO4)3.24H2O
Where,
X : Monovalent cation
M: Trivalent metal
o Potash Alum and its uses :
 Potash Alum - K SO Al (SO ) .24H O
2 4 2 4 3 2
 Potash alum is used in papermaking, in fire extinguishers, in food

stuffs and in purification of water. Soda alum is used in baking
powders and chrome alum is used in tanning leather and water
proofing fabrics.
 It is also used :
 As an Astringent: A substance or preparation, that draws
together or constricts body tissues and is effective in stopping
the flow of blood or other secretions. Alum has also been
used by conventional hairdressers for treating shaving cuts.
 As a Mordant: Substances used in dyeing to fix certain dyes
on cloth. Either the mordant (if it is colloidal) or a colloid
produced by the mordant adheres to the fiber, attracting and
fixing the colloidal mordant dye. The insoluble, colored
precipitate that is formed is called a lake. Alum is a basic
mordant used for fixing acid dyes.
 To remove phosphate from water: The aluminum ions of
alum combine with the orthophosphate around pH 6 to form
the solid aluminum hydroxy phosphate which is precipitated.
 For fireproofing fabrics: The major use of alums are based on
two important properties, namely precipitation of Al(OH)3
and those related to the acidity created by the production of
hydrogen ions.
Al(H2O)6 +3 → Al(OH)3 ↓ +3H2O + 3H+
 The H+ ions generated are used for reacting with sodium
bicarbonate to release CO2 . This property is made use of in
baking powder and CO2 fire extinguishers.
 THEORY:
 Aluminum metal is treated with hot aqueous KOH solution.
Aluminum dissolves as potassium aluminate salt, KAl(OH)4 .
 Potassium aluminate solution on treatment with dil. sulphuric acid
first gives a precipitate of Al(OH)3 , which dissolves on addition of
small excess of H2SO4 followed by heating.
 The resulting solution is concentrated to near saturation and
cooled. On cooling, crystals of potash alum crystallize out.
 CHEMICAL EQUATIONS:
 2 Al + 2 KOH + 6 H O  2 KAl(OH)
(s) (aq) 2 (l) 4 (aq) + 3 H2
 K SO
2 4 (aq) + Al2(SO4)3 (aq) + 24 H2O(l)  K2SO4.Al2(SO4)3.24 H2O
 2 Al(OH) 3 (s) + 3 H2SO4 (aq)  Al2(SO4)3 (aq) + 6 H2O (l)
 2KOH (aq) + H2SO4 (aq)  2 Al(OH)3 (s) + K2SO4 (aq) + 2 H2O (l)
 K SO
2 4 (aq) + Al2(SO4)3 (aq) + 24 H2O (l)  K2SO4.Al2(SO4)3. 24 H2O
 MATERIALS USED
o Apparatus:
 250ml Measuring Flask
 Funnel
 Filter Paper
 Beaker
 Water Bath
 Ice Bath
o Chemicals used:
 Scrap Aluminum
 Potassium hydroxide Solution (KOH)
 6 M Sulphuric Acid (H2SO4)
 Ethanol
 PROCEDURE:
o Take a small piece (approx.. 1 g) of scrap aluminum (aluminum
foil), and clean it using steel wool. Cut this foil into small pieces.
o Put these pieces of aluminum into a conical flask. Add 50 ml of 4 M
KOH solution to this flask to dissolve the aluminum.
o Heat the flask using a water bath setup, in order to facilitate
dissolution. Hydrogen gas is evolved. Continue heating until all the
aluminum has reacted.
o Filter this solution to remove any insoluble impurities and reduce
the volume to about 25 ml by heating.
o Allow the filtrate to cool. Now add slowly 6 mh2so4 until insoluble
Al(OH)3 just forms in the solutions.
o Gently heat the mixture until the Al(OH)3 precipitate dissolves.
o Cool the resulting solution in an ice-bath for about 30 minutes
whereby alum crystals should separate out. For better results the
solution may be further concentrated and cooled again.
o In case crystals do not form, the solution may be further
concentrated and cooled again.
o Filter the crystals from the solution using vacuum pump, wash the
crystals with 50/50 ethanol-water mixture.
o Continue applying the vacuum until the crystals appear dry.
o Determine the mass of alum crystals.
 OBSERVATIONS:
 Mass of aluminum metal = 2.39 g
 Mass of potash alum =4.67 g
 Theoretical yield of potash alum =5.43 g

 Percent yield =86 %
 RESULTS:
o Potash alum was prepared from aluminum\ scrap.
 BIBLIOGRAPHY:
o http : //www.cbseportal.com
o Wikipedia
o chemicalland.com
o books.google.co.in
THANK
YOU
fin.

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CHEMISTRY

conducted by AISSCE, New Delhi.

Date: School stamp Principal’s Signature

Signature of external examiner Signature of subject teacher

7. CONCLUSION AND ANALYSIS

 Potash alum is used in papermaking, in fire extinguishers, in food

 2 Al(OH) 3 (s) + 3 H2SO4 (aq)  Al2(SO4)3 (aq) + 6 H2O (l)

 Theoretical yield of potash alum =5.43 g

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