Investigatory Project on Metal coupling

mmmmmmmmmmmm Investigatory project on "Efect o metal coupling on rusting o iron." By BY SHREYA RANI Shreya Rani 1

Certificate This is to certify Shreya Rani of class 11 -sci. to complete the project title !St"y of effect of metal co"plin# on r"stin# of Iron$ sincerely an satisfactorly "ner the #"iance an s"per%ision chemistry teacher &rs 'rachi Sin#h ( in ).A.* '"+lic School ( ,asola *ihar ithin the stip"late time as prescri+e +y BSE.

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Acknowledgement :

  I would like to express my gratitude to Mrs Prachi our chemistry teacher whose help and encouragement made this project possi!le. I would also like to thanks the a! #ssistant or his help during the completion o this project. 

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4Introduction......................................

.............+ 4 Methods o Prevention o ,orrosion....4 #im o the project........................................ 4%e/uirement..................................... ..............0 4 1heory...............................................

INTRODUCTION Metals and alloys undergo rusting and corrosion. The process by which some metals when exposed to atmospheric condition i.e. moist air carbon dioxide !orm undesirable compounds on the sur!ace is "nown as corrosion The compounds !ormed are usually oxides . Rusting is also a type o! corrosion but the term is restricted to iron or products made !rom it .Iron is easily prone to rusting ma"ing its sur!ace rough.

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ðos to pre%ent r"stin# are as follo6 1) Barrier Protection : In : the metho ( a +arrier film is intro"ce +eteen iron s"rface an atmospheric air. The film is o+taine +y paintin#(%arnishin# etc. 2)Galvanisation6In 2)Galvanisation this metho iron is co%ere +y a more reacti%e metal s"ch as 7inc hich losses electrons in preference of iron. Th"s( protectin# from r"stin# an corrosion.

#IM

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In this project the aim is to in%esti#ate effect of the metal co"plin# on the r"stin# of iron. &etal co"plin# affects the r"stin# of iron if the nail is co"ple ith a more electro-positi%e metal li9e 7inc( ma#nesi"m or al"mini"m r"stin# is pre%ente +"t if on the other han ( it is co"ple ith less electro : positi%e metals li9e copper ( the r"stin# is facilitate.

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%E78I%EME91$ &*1wo Petri dishes 4*,hina dish  5* :our iron nails  6* 1 ripod stand +* $and paper -*;ire gauge  * magnesium strips 2* Phenolphthalein ?In preparation &@*Potassium erocynide o agarAagarB

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 1heory

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4  hemically( r"st is a hyrate ferric o=ie Titanic>s +o e=hi+itin# micro+ial corrosion ama#e in the form of >r"sticles? R"stin# an Electrochemical &echanism @ R"stin# may +e e=plaine +y an electrochemical mechanism. In the presence of moist air containin# issol%e o=y#en or car+on io=ie( the commercial iron +eha%e as if compose of small electrical cells. At anoe of cell( iron passes into sol"tion as ferro"s ions. The electron mo%es toars the cathoe an form hyro=yl ions. ner the infl"ence of issol%e o=y#en the ferro"s ions an hyro=yl ions interact to form r"st( i.e.( hyrate ferric o=ie.

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In the presence of moist air containin# issol%e o=y#en or car+on io=ie( the commercial iron +eha%es as if compose of electrical cells.  At anoe of cell( iron passes in to sol"tion as ferro"s ions. 1. Ce Ce2D D 2eThe electrons from the a+o%e reaction . mo%e toars the cathoe an form hyro=yl ions H2 D FG D 2e2H ner  the infl"ence of issol%e o=y#en the ferro"s ions an hyro=yl ions interact from r"st(i.e.( hyrate ferric o=ie. 2Ce2D DH2 DFG 2CeD D 2H2CeD D HCe2.H2 Fr"stG or 2CeFHG  1

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PROCEDURE  nnnnnn

&$#t %rst sur!ace o! iron nails were cleaned

with the help o! sand paper.  &$ #!ter that 'inc strip was winded around one nail a clean copper wire around the second ( clean magnesium strip around the third nail. Then these three and a !ourth nail were put in)etri dish so that they were not in contact with each other. *$ Then)etri dish was %lled with hot agar agar solution in such a way that only lower hal! o! the nails was co+ered with the li,uid .)etri dish was co+ered !or one day or so 11

-RI#/ NO.

MT#/ )#IR

CO/OUR O0 )#TC1

N#I/- RU-T OR NOT

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%esult

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The li,uids set to a gel on cooling. Two types o! patches were obser+ed around the rusted nail one was blue and the other pin". 2lue patch was due to the !ormation o! potassium !erro3 oooooooooooooooo !erricyanide whereas pin"1

CONC/U-ION

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It is clear from the o+ser%ation that co"plin# of iron ith more electropositi%e metals s"ch as 7inc an ma#nesi"m resists corrosion an r"stin# of iron. o"plin# of iron ith less electropositi%e metals s"ch as copper increases r"stin#. !!!!!!!!!!!!!!!!!!!!!!!!!!

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