corrosion vs oxidation (1 Viewer)

Farmerism

Member
Joined
Aug 15, 2005
Messages
57
Gender
Female
HSC
2006
just wondering

if a metal corrodes, is it being oxidised or reduced
 
P

pLuvia

Guest
Wouldn't it be oxidised because the oxygen reacts with the metal to form an oxide
 

Farmerism

Member
Joined
Aug 15, 2005
Messages
57
Gender
Female
HSC
2006
hm yeah i guess so. but now im confused about another thing.

with reference to galvanising. um.. is what i have to say below true?

zinc is more readilly oxidised than iron. since zinc is being used to protect the iron from corrosion (which is what happens when the iron oxidses), when it is scratched ...........

no wait im confused here. when iron 'corrodes' isnt it accepting electrons? ..... because Fe^2+ + 2e -> Fe...

no wait.. when iron corrodes it should be Fe -> Fe^2+ + 2e because Fe ions break off the crystal lattice and become Fe^2+?....

can anyone see where my problem is.. im confused about whats oxidised and whats reduced in the galvanising protection thing....

the above was just my thinking process. hope it didnt make anyone dumber
 
P

pLuvia

Guest
Farmerism said:
hm yeah i guess so. but now im confused about another thing.

with reference to galvanising. um.. is what i have to say below true?

zinc is more readilly oxidised than iron. since zinc is being used to protect the iron from corrosion (which is what happens when the iron oxidses), when it is scratched ...........

no wait im confused here. when iron 'corrodes' isnt it accepting electrons? ..... because Fe^2+ + 2e -> Fe...

no wait.. when iron corrodes it should be Fe -> Fe^2+ + 2e because Fe ions break off the crystal lattice and become Fe^2+?....

can anyone see where my problem is.. im confused about whats oxidised and whats reduced in the galvanising protection thing....

the above was just my thinking process. hope it didnt make anyone dumber
Zinc acts as the sacrificial anode which is the metal which protects iron from being oxidised.

When iron corrodes it is being oxidised so it loses electrons which is called the anodic site, and where reduction occurs is called the cathodic site.

So:

Fe2+ ---> Fe(s)+2e-

Some impurities such as carbon, where these electrons can flow, where carbon can act as a cathode if present. The oxygen dissolved in where the water touches the metal is where reduction occurs
 
Last edited by a moderator:

pkc

Member
Joined
Apr 16, 2006
Messages
155
Gender
Male
HSC
N/A
do you mean

Fe^2+ + 2e- ---> Fe (s) ?




How do you make superscripts anyway???
 
P

pLuvia

Guest
Well I didn't mean that, but because iron is oxidised it loses electrons, but the actual half equation I meant was:

Fe(s)--->Fe2++2e-

To do subscripts and superscripts

Fe[ sub ](s)[/ sub]--->Fe[ sup]2+[/ sup]+2e[ sup]-[/ sup]

Without the spaces
 

suebear

New Member
Joined
May 2, 2006
Messages
2
Gender
Female
HSC
N/A
Farmerism said:
just wondering

if a metal corrodes, is it being oxidised or reduced


the one that corodes is the one being oxidised
 

tartaresauce

New Member
Joined
Nov 20, 2005
Messages
7
Gender
Male
HSC
2006
corrosion of iron is when it gets oxidised. the equation should be
Fe(s) -> Fe^2+(aq) + 2e-
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top