Coin Investigatory)

Chemistry Project On Coin Analysis Prepared By: Saumya Kharya XII – A Session : 2011-2012 Board Roll Number : Father Agnel School

AIM

Qualitative Analysis Of Different Coins

CERTIFICATE This is hereby to certify that, the original and genuine investigation work has been carried out to investigate about the subject matter and the related data collection and investigation has been completed solely, sincerely and satisfactorily by Saumya Kharya of Class-XII,Father Agnel School, regarding her project titled “Qualitative Analysis of Coins”.

Teacher’s Signature

ACKNOWLEDGEMENT It would be my utmost pleasure to express my sincere thanks to My Chemistry Teacher Mrs. Jyoti Verma, in providing a helping hand in this project. Her valuable guidance, support and supervision all through this project titled “Qualitative Analysis of Coins”, is responsible for attaining its present form.

Saumya XII

PURPOSE I was interested in finding out the contents of the coins we use in everyday life money transactions. Humans have been using coins since their invention in 700 B.C. for trading of goods and services. Another fact which inspired me to do this project is that I am in touch with qualitative analysis whose knowledge with other factors helped me to do so.

CONTENTS Introduction Theory Apparatus Chemicals Required 20 Paise Coin(India) 1 Cent Coin(U.S.A) 2 Rupee Coin(India) 1 Rupee Coin(India) Result Conclusion

INTRODUCTION An alloy is a mixture or metallic solid solution composed of two or more elements.Complete solid solution alloys give single solid phase-microstructure. Alloys usually have different properties from those of the component elements. Alloying a metal is done by combining it with one or more other metals or non-metals that often enhance its properties.Alloys are used in ornaments, bells, statues, buildings, and even coins.

Coins-A Historical Approach The history of coins extends from ancient times to the present, and is related to economic history, the history of minting technologies, and the history of coin collecting. Coins are still widely used for monetary and other purposes. Since the time they were invented in 700 B.C., coins have been the most universal embodiment of money. The first coins were made of electrum, a naturally occurring pale yellow mixture of gold and silver that was further alloyed with silver and copper. Some of the earliest coins were beaten at the edges to imitate the shape of a cow, in indication of their value. Most coins are circular but some were rectangular. Also a lot of coins, especially in China had a hole through the center so they could be tied on to a string.Some of the earliest coins to be made purely from silver and gold were the silver Dirham and gold Dinar. Coins were first made of scraps of metal. Ancient coins were produced through a process of hitting a hammer positioned over an anvil.The Chinese produced primarily cast coinage, and this spread to South-East Asia and Japan. The type of mintage method (being hammered, milled or cast) does limit the materials which can be used for the coin. For example antimony coins, (which are very rare) are nearly always cast examples, because of the brittle nature of the metal, and thus it would break if deformed, which is a key part of the milling or hammering process. Coins today are of great value and are used in our day-to-day lives.

THEORY A coin is a piece of hard material that is standardized in weight, is produced in large quantities in order to facilitate trade, and primarily can be used as a legal tender token for commerce in the designated country, region, or territory. Coins are usually metal or a metallic material and sometimes made of synthetic materials, usually in the shape of a disc, and most often issued by a government. Coins are used as a form of money in transactions of various kinds, from the everyday circulation coins to the storage of large numbers of bullion coins. In the present day, coins and banknotes make up currency, the cash forms of all modern money systems. An alloy is a homogeneous mixture of two or more metals or a metal and nonmetal. They are generally harder than their components with reduced malleability and ductility. Alloys are prepared to enhance certain characteristics of the constituent metals, as per requirement. The coinage metals comprise, at minimum, those metallic chemical elements which have historically been used as components in alloys used to mint coins. Coins that are intended for circulation have some special requirements based on the conditions they will encounter. For example, a coin may be in circulation for up to 30 years, and so must have excellent wear resistance and anticorrosion properties. Achieving this goal necessitates the use of base metal alloys. Some metals like manganese have occasionally been used in coins, but suffer from making the coins too hard to take an impression well . A common base metal alloy for everyday coinage is CuproNickel (also cupronickel), with varying proportions of copper and nickel, most commonly 75% Cu 25% Ni. Cupronickel has a silver color, is hard wearing and has excellent striking properties, essential for the design of the coin to be pressed accurately and quickly during manufacture.

APPARATUS Test Tubes Test Tube Holder Test Tube Stand Beaker Burner Tripod Stand pH Paper Wire Gauge Water Bath Filter Paper

CHEMICALS REQUIRED Hydrochloric Acid (HCl) Sodium Hydroxide Hydrogen Sulphide Gas Nitric Acid (HNO3) Ammonium Acetate Potassium Iodide Potassium Chromate Potassium Ferrocyanide Ammonium Hydroxide Ammonium Chloride Potassium Sulphocyanide Potassium Nitrite Ammonium Thiocyanide Dimethyl Glyoxime Bromine Water Ammonium Carbonate Ammonium Phosphate

Twenty Paise Coin (India)Made in 2003 Experiment

Observation

Zero Group: Add concentrated solution of No white fumes observed. sodium hydroxide(NaOH) to it. Group I: Add dilute solution of No white precipitate formed. hydrochloric acid to the original solution. Group II: Add dilute solution of HCl to the original solution and pass H2S gas through it.

No black or yellow precipitate formed.

Inference Ammonia(NH4+) is absent.

Pb2+,Ag2+ and Hg22+ are absent.

Pb2+,Cu2+,As3+ are absent.

Group III: Add NH4Cl and NH4OH(in A white precipitate is obtained. Al3+ may be present. excess) to the original solution.

Confirmatory For Al3+: Lake Test: Dissolve the white precipitate obtained int dilute HCl. Add to it two drops of blue litmus solution. To this, add NH4OH drop wise till blue colour develops.

Group IV: Use the same solution as used in Group III tests and pass H2S gas through it. Group V: To the original solution, add NH4Cl, NH4OH and (NH4)2CO3. Group VI: To the original solution, add NH4Cl, NH4OH(in excess) and (NH4)2HPO4.

Blue precipitate is observed floating in the colourless solution.

Al3+ is present.

No precipitate formed.

Co2+,Ni2+,Mn2+ and Zn2+ are absent.

No white precipitate formed.

Ba2+,Ca2+ and Sr2+ are absent.

A white precipitate is obtained. Mg2+ may be present.

RESULT Twenty Paise Coin of India contains Aluminium(Al3+)and Magnesium(Mg2+).

One Cent Coin(U.S.A)Made in 1987 Experiment Zero Group: Add concentrated solution of sodium hydroxide(NaOH) to it. Group I: Add dilute solution of hydrochloric acid to the original solution. Group II: Add dilute solution of HCl to the original solution and pass H2S gas through it.

Observation

Inference

No white fumes observed.

Ammonia(NH4+) is absent.

No white precipitate formed.

Pb2+,Ag2+ and Hg22+ are absent.

A black precipitate obtained.

Cu2+ may be present.

Confirmatory for Cu2+: Heat the black precipitate with 1-2 ml of 50% HNO3.The precipitate dissolves and add Blue coloured solution obtained. Cu2+ may be present. dilute H2SO4 and alcohol. When there is no white precipitate,add NH4OH in excess. Potassium ferrocyanide test: To one part of the blue solution A chocolate brown precipitate is Cu2+ is present. add acetic acid and potassium obtained. ferrocyanide solution. Potassium Iodide test: A white precipitate is formed in To another part add acetic acid the brown coloured solution. and potassium iodide solution. Group III: Add NH4Cl and NH4OH(in A white precipitate is obtained. excess) to the original solution. Group IV: Use the same solution as used A dull white precipitate is in Group III tests and pass H2S obtained. gas through it.

Cu2+ is present.

Al3+,Cr3+,Fe3+,Fe2+ are absent.

Zn2+ may be present.

Confirmatory for Zn2+: Sodium hydroxide test: To one part of the original A white precipitate is obtained. Zn2+ is present. solution add sodium hydroxide Add more NaOH to dissolve the solution drop-wise. precipitate. Potassium ferrocyanide test: To another part, add potassium ferrocyanide solution.

A white or bluish white precipitate.

Zn2+ is present.

RESULT Twenty Paise Coin of India contains Zinc(Zn2+) and Copper(Cu2+).

Two Rupees Coin (India)Made in 2003 Experiment

Observation

Zero Group: Add concentrated solution of No white fumes observed. sodium hydroxide(NaOH) to it. Group I: Add dilute solution of hydrochloric acid to the original solution. Group II: Add dilute solution of HCl to the original solution and pass H2S gas through it.

Inference Ammonia(NH4+) is absent.

No white precipitate formed.

Pb2+,Ag2+ and Hg22+ are absent.

A black precipitate obtained.

Cu2+ may be present.

Blue coloured solution obtained.

Cu2+ may be present.

Confirmatory for Cu2+: Heat the black precipitate with 1-2 ml of 50% HNO3.The precipitate dissolves and add dilute H2SO4 and alcohol. When there is no white precipitate,add NH4OH in excess.

Potassium ferrocyanide test: To one part of the blue solution A chocolate brown precipitate add acetic acid and potassium is obtained. ferrocyanide solution. Potassium Iodide test: To another part add acetic acid and potassium iodide solution.

Cu2+ is present.

A white precipitate is formed in Cu2+ is present. the brown coloured solution.

Group III: Add NH4Cl and NH4OH(in A white precipitate is obtained. excess) to the original solution.

Al3+,Cr3+,Fe3+,Fe2+ are absent.

Group IV: Use the same solution as used A black precipitate is obtained. in Group III tests and pass H2S gas through it.

Ni2+ may be present.(If the original solution is green).

Confirmatory for Ni2+: Dimethyl glyoxime test: To one part of the original solution add ammonium hydroxide solution and few drops of dimethyl glyoxime. Sodium hydroxide - bromine water test: To another part add sodium hydroxide (in excess) and bromine water and boil.

A bright rose red precipitate is obtained.

Ni2+ is present.

A black precipitate is obtained.

Ni2+ is present.

RESULT Two Rupee Coin of India contains Copper(Cu2+) and Nickel(Ni2+).

One Rupee Coin (India)Made in 2010 Experiment

Observation

Zero Group: Add concentrated solution of No white fumes observed. sodium hydroxide(NaOH) to it. Group I: Add dilute solution of hydrochloric acid to the original solution. Group II: Add dilute solution of HCl to the original solution and pass H2S gas through it.

No white precipitate formed.

Inference Ammonia(NH4+) is absent.

Pb2+,Ag2+ and Hg22+ are absent.

Pb2+,Cu2+,As3+ are absent. No black or yellow precipitate formed.

Group III: Add NH4Cl and NH4OH(in A reddish brown precipitate is excess) to the original solution. obtained.

Fe3+ may be present.

Confirmatory for Fe3+: Dissolve the reddish brown precipitate in dilute HCl, and divide the solution into two parts. Potassium ferrocyanide test: To one part of the above solution add potassium ferrocyanide solution.

Prussian Blue colouration is obtained.

Potassium sulphocyanide test: To the second part, add a little Blood red colouration is potassium sulphocyanide obtained. solution.

RESULT Two Rupee Coin of India contains Iron(Fe3+).

Fe3+ is present.

Fe3+ is present.

RESULT Amount

Country

Year

Ions present

Twenty Paise Coin India

1938

Al3+ and Mg2+ ions

One Cent Coin

U.S.A

1987

Cu2+ and Zn2+ ions

Two Rupee Coin

India

2003

Cu2+ and Ni2+ ions

One Rupee coin

India

2010

Fe3+ ion

BIBLIOGRAPHY LABORATORY MANUAL OF CHEMISTRY BY- VEENA SURI

DINESH COMPANION CHEMISTRY BY- S.K. MALHOTRA

WEBSITES — 

http://www.wikipedia.com

 http://www.cbseprotal.com