Chemistry Assignment No-2.

Subject : Chemistry

Teacher : Mr.Pankaj Vikas Thakur (H.O.D)

      

1. Iron corrodes faster than Al,even though iron is played below aluminium in electrochemical
series .why?
2. How is galvanization different from cathodic protection?
3. Rusting of iron is quicker in saline water than in ordinary water.why?
4. Why does corrosion occurs in steel pipes connected to copper plumbing?
5. Bolt and nuts made of the same metal are preferred in practice.why?
6. State the two conditions for wet corrosion to take place?
7. Why does a part of nail inside the wood undergo corrosion easily?
8. Why should nickel plated steel articles be free from pores and pin holes?
9. Why deposition of extra matter on the surface of the metal is undesirable?
10. Comment on use of AL in place of Zn for cathodic protection of iron?
11. Galvanized containers are not used for storage of food products,but tin coated containers are.
Comment?
12. Why does corrosion of water filled water tanks occure below the waterline?
13. A piece of pure zinc and impure zinc are placed in a salt solution.which will corrode faster?
14. What is the effect of pH on corrosion?
15. Where the electrochemical corrosion takes place?
16. What is the effect of carbon dioxide on electrochemical corrosion?
17. Formation of which type of metal oxide film prevents corrosion?
18. Formation of which type of metal oxide film cause corrosion?
19. What is the requirement of the coating metal to act as sacrificial anode?
20. What is the chemical formula of rust?
21. Define sheradizing?
22. Define colorizing?
23. What is chromizing?