chemistry project class xii
TRANSCRIPT
-
8/14/2019 CHEMISTRY PROJECT class XII
1/15
CHEMISTRY PROJECT
PREPARATION OF POTASH
ALUM FROM SCRAP
ALUMINIUM
KAPIL KUMAR
XIITH C3
ROLL NO. -123123132
GREENFIELDS PUBLIC SCHOOL
-
8/14/2019 CHEMISTRY PROJECT class XII
2/15
CERTIFICATE
It is to hereby certify that, the original and genuine
research work is carried out to investigate aboutthe subject matter and the related data collection
has been completed solemnly and satisfactorily by
Kapil Kumar of class XII C3 regarding the project
Preparation of Potash Alum from Scrap
Aluminium
Signature
(Mrs. Rekha Chopra)
-
8/14/2019 CHEMISTRY PROJECT class XII
3/15
ACKNOWLEDGEMENTS
I would like to thank my chemistry teacher Mrs. Rekha
Chopra for her guidance and support. I also like tothank my Principal Mrs. M. Barsaley. I would also like
to thank my parents and my classmate for encouraging
me during the course of this project.
Kapil Kumar
-
8/14/2019 CHEMISTRY PROJECT class XII
4/15
Introduction
Aluminium because of its low density, high tensile
strength and resistance to corrosion is widely used for
the manufacture of aeroplanes, 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 arethe alums.
Alums are double sulphates having general formula:-
X2SO4.M2(SO4)3.24H2O
-
8/14/2019 CHEMISTRY PROJECT class XII
5/15
Some important alums and their names are given
below:
K2SO4.Al2(SO4)3.24H2O- Potash Alum
Na2SO4.Al2(SO4)3.24H2O- Soda Alum
K2SO4.Cr2(SO4)3.24H2O- Chrome Alum
(NH)2SO4.Fe2(SO4)3.24H2O- Ferric Alum
Potash alumis used in papermaking, in fire
extinguishers, in food stuffs and in purification of
water.
Soda alumused in baking powders and chrome alumis
used in tanning leather and water proofing fabrics.
-
8/14/2019 CHEMISTRY PROJECT class XII
6/15
In addition to these primary uses, alum is also used as
i) An astringent. A substance or preparation, thatdraws together or constricts body tissues and iseffective 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 fixcertain dyes on cloth. Either the mordant or a
colloid produced by the mordant adheres to thefiber, 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.
iii) For the removal of phosphate from natural andwaste waters.The aluminium ions of alum
combine with the orthophosphate around pH 6
to form the solid aluminium hydroxyphosphate
which is precipitated.
iv) For fireproofing fabrics.
-
8/14/2019 CHEMISTRY PROJECT class XII
7/15
Aim
To prepare potash alum from
aluminium scrap.
-
8/14/2019 CHEMISTRY PROJECT class XII
8/15
Apparatus
250 ml flaskFunnelBeakerScrap aluminium or cola canPotassium hydroxide solution(KOH)6 M Sulphuric Acid (H2SO4)Water BathEthanol
-
8/14/2019 CHEMISTRY PROJECT class XII
9/15
Theory
Aluminum metal is treated with hot aqueous KOH
solution. Aluminium dissolves as potassium aluminate,
KAl(OH)4, salt.
Potassium aluminate solution on treatment with dil.Sulphuric acid first gives precipitate Al(OH)3, which
dissolves on addition of small excess of H2SO4and
heating.
The resulting solution is concentrated to near
saturation and cooled. On cooling crystals of potash
alum crystallize out.
-
8/14/2019 CHEMISTRY PROJECT class XII
10/15
Reactions
-
8/14/2019 CHEMISTRY PROJECT class XII
11/15
Procedure
Clean a small piece of scrap aluminium with steelwool and cut it into very small pieces. Aluminium
foil may be taken instead of scrap aluminium.
Put the small pieces of scrap aluminium oraluminium foil (about 1.00g) into a conical flask andadd about 50 ml of 4 M KOH solution to dissolve
the aluminium.
The flask may be heated gently in order tofacilitate 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
H2SO4until insoluble Al(OH)3just forms in the
solution.
-
8/14/2019 CHEMISTRY PROJECT class XII
12/15
Gently heat the mixture until the Al(OH)3precipitate dissolves.
Cool the resulting solution in an ice-bath for about30 minutes whereby alum crystals should separateout. For better results the solution may be left
overnight for crystallization to continue.
In case crystals do not form the solution may befurther concentrated and cooled again.
Filter the crystals from the solution using vacuumpump, wash the crystals with 50/50 ethanol-water
mixture.
Continue applying the vacuum until the crystalsappear dry.
Determine the mass of alum crystals.
-
8/14/2019 CHEMISTRY PROJECT class XII
13/15
Observations
Mass of aluminium metal = __________g
Mass of potash alum = __________g
Theoretical yield of potash alum = __________g
Percent yield = __________%
-
8/14/2019 CHEMISTRY PROJECT class XII
14/15
Result
Potash alum was prepared fromaluminium scrap.
-
8/14/2019 CHEMISTRY PROJECT class XII
15/15
Bibliography
www.cbseportal.comWikipedia
Chemicalland.com
books.google.co.in