RYAN INTERNATIONAL SCHOOL GHAZIABAD SESSION: 2014-15
INVESTIGAT INVESTIGATORY ORY REPORT ON
Rustin O! I"#n Su$%itt&' B(: Gun)it A*"+*, C,*ss 12t
AC.NO/LEDGEENT I am thankful to take this opportunity to place on record my sincere gratitude towards Mrs.Preeti Jain who gave her valuable guidance and help and was accessible throughout my project work. I thank her for having put her considerable experience and knowledge at our disposal. Further, I acknowledge the support of the infrastructure of the school premises and the lab used for the same valuable purpose.
CERTIICATE
This is to certify that investigatory project on the topic “Rusting of Iron” has been successfully done by Gunjit Aggarwal of Class 12th for the practical examination 2015.It is further certified that this project is individual work of the candidate.
Chemistry Teacher
INTRODCTION Iron is one of the widely distributed elements in the nature. One of its striking characteristics is that it undergoes rusting on combining with water, air & carbon-dioxide due to which its surface gets covered with a red brown flake coating called "R!". R! is affected by moisture, oxygen & carbon - dioxide. R! is soft and
#orous and it gradually falls off from the surface of iron material. It is a continuous #rocess and it gradually eats u# iron due to which an iron ob$ect loses its strength. It is very wasteful #rocess and should be #revented. It is very-very slow #rocess.
AI To study the effect of usting on Iron !ails in different solutions.
THEORY "hen a piece of iron metal is exposed to humid atmosphere, its gets covered with a red brown substance called #ust#. usting of iron can be explained on the basis of electro C$%&IC'( T$%)* as follows + . "ater vapours on the surface of the metal dissolved carbondioxide and oxygen from the air. Thus the surface of metal is covered with the solution of carbon-dioxide with water, i.e. carbonic acid +!2" # C"2 $$$$$$% !2C"& '''''''''' (i) This acts as an electrolytic solution of the cell. The carbonic acid and water dissociate to a small extent as follows+ !2C"& *$$$$$$% 2 !# #C"&2' !2" *$$$$$$% !# #"!' '''''''''' (ii)
. Iron in contact with the dissolved C) and ) undergoes oxidation as follows ++e $$$$$$$$$% +e## # 2e, '''''''''''''(iii) 's a result iron is converted into ferrous /Fe001 ion.
2. The electrons lost by iron are taken up by the $0 ions present on the surface of metal which were produced by the dissociation of $C)2 and $). Thus $0 ions are converted into $atoms. !# # e, $$$$$$$% ! ''''''''''' (i-) Thus $ atoms either react with the dissolved oxygen or oxygen from air to from water. ! # "2 $$$$$$% 2!2" '''''''''' (-) The complete reaction may be written as +"2# !# # e, $$$$$$%2 !2" ''''''' (-i) The dissolved oxygen may take up electrons directly to from )$3 ions as follows + "2 # 2!2" # e, $$$$$$% "!, ''''''(-ii) The over all reaction of the miniature cell will be +2+e(s) # "2(g) # !# (a/) $$$% 2+e##(a/)#2!2"(l) 4. The ferrous ions formed react with the dissolved oxygen or oxygen from air to from ferric oxid as follows + +e## # "2 # !2" $$$$$$% 2+e2"& # !# (a/) Ferric oxide then undergoes hydration to form 56T as follows ++e2"& # !2" $$$$$$$% +e2"& !2" $ydrated ferric oxide /56T1
APPARATS RE3IRED i1 7oiling tubes ii1 ubber stopper iii1 Iron nails iv1 7urner v1 Test tube, $older 8 6tand
CHEICALS RE3IRED i1 9istilled "ater ii1 9ilute $C( iii1 9ilute !aCl 6olution iv1 'nhydrous Calcium Chloride v1 Cotton vi1 &ustard )il
PROCEDRE
i1 Take five dry test tubes and mark them ', 7, C, 9 and %. Take : pieces of iron nails free from rust. ii1 &oist two iron nails with distilled water and slide it in the test tube marked ;'< close the mouth of the tube. iii1 In the test tube ;7< take = ml of water and boil it so as to remove dissolved air. 6lide two nails in this test tube and few drops of mustard oil so as to cover the surface of $). iv1 In the test tube ;C< take = ml of dilute !aCl solution. 6lide two nails and close it. v1 In the test tube ;)< add two pieces of hydrous calcium chloride and cover it with thin layer of cotton. 'gain slide 2 nails and close it. vi1 leave these test tubes as such for 4-= days and observe carefully in which of the tubes rust is formed.
OBSERVATIONS i% It is observed that rusting takes #lace in the test tube and ' where as not in (, ), and *. ii% +oisture, oxygen and carbon-dioxide #resent in air are
res#onsible for rusting. iii% It a##ears that during a com#ound of iron is formed by the combination of iron oxygen, carbon-dioxide and water. iv% It is observed that when the #rocess was #rolonged in the #resence of moist air and acids, rusting s#reads uickly.
CONCLSION /i1 ust is formed by prolonged action of water oxygen and carbondioxide on an iron under other suitable conditions. /ii1 &oisture, )xygen and carbon-dioxide present in air, all responsible for rusting.
ETHODS O PREVENTION i1 usting of iron can be prevented by covering its surface with paints, grease and lac>uers. ii1 ?alvanisation +- This is one of widely practical methods used for the prevention of rusting. The layer of @inc on the surface of iron, when comes in contact with moisture, oxygen and carbon-dioxide in air, ferrous a protective invisible thin layer of basic Ainc carbonate @nC)2. @n/)$1 due to which the galvanised iron sheets lose their lusture and also tends to protect it from further corrosion. iii1 usting of iron can also be prevented by coating its surface with iron /II, III1 oxide Fe2)4 or iron /III1 phosphate FeBo4.
