Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
According to this theory, the impure iron surface behaves like a small electrochemical cell presence of water containing dissolved oxygen or carbon dioxide. Such a cell is also called corrosion cell or corrosion couple. In these miniature corrosion cells, pure iron acts as anode and impure surfaces acts as cathode. Moisture dissolved oxygen or carbon dioxide in it comprises electrolytic solution.
At anode, oxidization of Fe atoms takes place. Thus, Fe atoms pass into solution as Fe2+ ions leaving behind electrons in the metal which are pushed into cathodic area. Fe Fe+2 + 2e-; = - 0.44 V (i)
At cathode, the electrons are picked up by the H+ ions which are produced either from H2O or from H2CO3 (formed by dissolution of CO2in moisture). CO2 + H2O H+ + HCO3- 2H+(aq) + 2e- 2H The H atoms, thus, formed, reduce the dissolved oxygen as 2H + ½ O2 H2O The net reduction process at the cathodic area is 2H + ½ O2 + 2e- H2O; = 1.23 V (ii)
The net reaction of the corrosion cell can be obtained by adding equations (i) and (ii) F2 + 2H+ ½O2 2 Fe2+ + H2O; = 1.67 V The ferrous ions so formed move through water and come at the surface of iron object where these are further oxidized to ferric state by atmospheric oxygen and constitute rust which is hydrated iron (III) oxide. 2Fe2+ + ½ O2 + 2H2O Fe2O3 + 4H+ Fe2+ + xH2O Fe2O3xH2O (rust)
determination of lattice energy
An element L has 9 protons and valency 1. Another element M has valency 3 and 5. What is the difference in the number of electrons in L and M ?
what are alkanes
A solution is made by dissolving30 g of a non-volatile solute in 90 g of water. It has a vapour pressure of 2.8 kPa at 298 K. At 298 K, vapour pressure of pure water is 3.64 kPa
which is more acidic among o-methoxy benzoic acid and m-methoxy benzoic acid Ans) O-methoxy benzoic acid is more acidic than m-metoxy benzoic acid.
What is the chemical formula for hard water?
strain theory
lithium and beryllium markedly different from other members of their respectively groups
Why there are tie lines for 3 phase equilibrium however not for 2-phase equilibrium in a two-component system? Lever rule derived from mass balance gives the relative amounts o
Q. Illustrate the Physical properties of Ammonia? Ans. Ammonia is a colorless gas that has a strong penetrating odor. It boils at -33 o C and is easily liquefied by press
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd