This document is a chemistry investigatory project report on the preparation of potash alum from aluminium scraps. It includes an introduction describing alums and their uses, the aim of preparing potash alum, a list of required apparatus and materials, theoretical background on the reactions involved, step-by-step procedures followed, observations recorded, and conclusions drawn. The student expresses gratitude to teachers and principals for their support and guidance in completing the project.

1. CHEMISTRY INVESTIGATORY
PROJECT
Izak George
Parvathy Subash
Aishwarya
Alsa

2. PREPARATION OF POTASH
ALUM FROM ALUMINIUM
SCRAPS

3. ACKNOWLEDGMENT
Through this acknowledgment, I express my sincere gratitude toall
those people who have associated with the project and have helped me
with it and made it a worthwhile experience
I extend my thanks to Mrs. Anu George the principal of this fine
establishment Mar Dionysius Senior Secondary School Mallappally for
being pillar of support throughout the process
I would like to express my gratitude towards my parents for their
cooperation and encouragement which helped me in the completion of
the project
I would also like to express my thanks to Lincy, Chemistry teacher
who gave me this opportunity to learn the subject with a practical
approach, guided me and gave me valuable suggestions regarding the
project.

4. INDEX
 CERTIFICATE OF EXCELLENCE
 DECLARATION
 ACKNOWLEDGEMENT
 INTRODUCTION
 AIM OF THE PROJECT
 APPARATUSREQUIRED
 THEORY
 REACTIONS
 PROCEDUREFOLLOWED
 OBSERVATION
 CONCLUSION
 PRECAUTION
 BIBLIOGRAPHY

5. INTRODUCTION
Aluminium because of its low density, high tensile strength and
resistance to corrosion is widely used for the manufacture of aero
planes, automobiles lawn furniture as well as for aluminium cans.
Being good conductor of electricity it is used for transmission of
electricity. Aluminium is also used for making utensils. The recycling
of aluminium cans and other aluminium products is a very positive
contribution to saving our natural resources. Most of the recycled
aluminium is melted and recast into other aluminium metal products
or used in the production of various aluminium compounds, the most
common of which are the alums, Alums arc double sulphates having
generalformula:-

6. X3Sa.M>(SQ<),.24H20
X = Monovalcntcation: M = Trivalentcation;
Some importantalum and their names are given below:
^K^S04Al2(S04).1.24H20 -Potash Alum
v^Na^SO^MCSO^^l^O-Soda Alum
^K;S04.Cr2{S04),.24H:0 -Chrome Alum
v^(NH)2S04.Fc2(S04^.24H20 -Ferric Alum
Potash alum is used in papermaking in fire extinguishers, in food stuffs
and in purification of water soda alum used in baking powders and
chrome alum is used in tanning leather and water proofing fabrics.
In addition to these primary uses, alum is also used as
i. 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,
ii. 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 die fiber, attracting and fixing the colloidal mordant
dye. The insoluble, colored precipitate fiat is formed is called a lake.
Alum is a basicmordantused for fixing acid ayes.
iii. For the removal of phosphate from natural and waste Waters the
aluminium ions of alum combine with the orthophosphate around pH 6
to form the solid aluminum hydroxyphosphate which is precipitated,
iv. For fireproofing fabrics:- The major uses of alums are based on two
important properties, namely precipitation of Al(OH)i and those related
to the acidity created by the production of hydrogen ions,

7. SM(H20+3—►AI(OH)4 + 3H20 + 3rf
The H+ generated are used foe reacting with sodium bicarbonate to
release CO2. This property is made use of in baking powder and CO2 fire
extinguishers.

8. AIM OF THE EXPERIMENT
To prepare potash alum from aluminium scrap.
APPARATUS REQUIRED
♦ 250 ml flask
♦ Funnel
♦ Beaker
♦ Scrap aluminium or cola can
♦ Potassium hydroxide solution (KOH)
♦ 6 M Sulphuric Acid (H2SO4)
♦ Water Bath
♦ Ethanol

9. THEORY
Aluminum metal is treated with hot aqueous KOH solution, Aluminium
dissolves as potassium aluminate. KAI(OH)4, salt
>2AU + 2KOH,^ * 6H20rt, 2KAI{OH)4,N) + 3H2
Potassium aluminate solution on treatmentwith dil. Sulphuricacid first
gives precipitate Al (OH)3 which dissolves on addition of small excess of
H>S04 and heating.
> 2KOH<*j3 + HiSO^^i 2Al(OHK<*, + K:SO^a*,> + 2H;0(|5 >2AI(OH), ,„+
3H2SO«a<)) A1,(S04),(a<|1 +6HA..
The resulting solution is concentrated to near saturation and cooled On
cooling crystals of potash alum crystallizeout.
>K3SOJ(„3 + AL (S^W *24H30 ,,3K2SO„,Ah(SO,),, 4HA*>

10. REACTIONS
> 2AIW +2KOH m + 6H20 ™* fl)2KAf(OH) 4(aq) + 3H2
* K2SO4(aq)+ Alz(S04)3(a^+24H20. :a^. (uKzSO^AIzCSO*^
24H20{S}
> 2AI(OH)3fs)+ 3 H2S04 ^ AbCSOJaw + 6l"bOtt
> 2KOH(ac(j+ H2S04(aq) S+ 2AI(OH)3(s) + ^SQ,M +
2H20{!)
> K2SO4 (aq) + Al2 (S04)3taq> +24H20» K2S04^Al2,(SO4)3(24H2O[!9

11. PROCEDURE
 Clean a small piece of scrap aluminium with steel wool and cut it
into very small pieces. Aluminium foil may be taken instead of
scrap aluminium.
 Put the small pieces of scrap aluminium or aluminium foil (about
1.00g) into a conical flask and add about 50 ml of 4 M KOH solution
to dissolve the aluminium
 The flask may be heated gently in order to facilitate dissolution.
Since during this step hydrogen gas is evolved this step must be
done in a well-ventilated area.
 Continue heating until all of the aluminium reacts.
 Filter the solution to remove any insoluble impurities and reduce
the volume to about 25 ml by heating.
 Allow the filtrate to cool Now add slowly 6 M H;SO,, until
insoluble Al (OH)3 just forms in the solution. Procedure.
 Gently heat the mixture until the Al(OH)3 precipitate dissolves.
 Cool the resulting solution in an ice-bath for about 30 minutes
whereby alum crystals should separate out. For better result the
solution may be left ovemight for crystallization to continue,
 In case crystals do not form the solution may be further
concentrated and cooled again,
 In case crystals do not form the solution may be further
concentrated and cooled again
 Filter the crystals from the solution using vacuum pump, wash the
crystals with 50/50 ethanol-water mixture.
 Continue applying the vacuum until the crystals appear dry.
 Determine the mass of alum crystals.

12. OBSERVATIONS
Mass of aluminium metal =... .......................g
Mass of potash alum = …………………………. g
Theoretical yield ofpotash alum =.......................... ,g
Percent yield = ………………………………%
CONCLUSION
Potash alum of....................................... % yield was
prepared from aluminium scrap.

13. PRECAUTIONS
 Handle the glass wares safely.
 Allow the time required to set
 Spray only required amountof water.

14. BIBILOGRAPHY
 HELPFROMINTERNET
o www.google.com
o www.wikipedia.org
o www.icbse.com
 INFORMATIONFROM LIBRARY
o HELPFROMTEACHERS