Corrosion in acidic environments (1 Viewer)

[barnzey]

Why is the corrosion process accelerated in acidic environments?
I thought it was because the production of OH- neutralises with the acid and by le Chateliers principle the production of OH- is increased.

 

[barnzey]

But wouldn't that decrease the pH as the acid-base reactions are used up, and in the end it would neutralise again, before the Hydroxy group can react with the Fe2+ ion and hence corrosion rate will only increase in neutral and acidic environments

 

[ilovechildren]

barnzy

what are u doing barnzy. Havent you finished school. Go on sing us a song

 

[barnzey]

For the intial arguement wouldn't the use of the hydroxy ions, cause the corrosion to stop as they are used in the corrosion process?

 

[aim54x]

pH affects corrosion. acidic accelerates it as well as basic i think. that sounds weird. lets hope some1 will clear this up.

 

[Xayma]

pH affects corrosion. acidic accelerates it as well as basic i think. that sounds weird. lets hope some1 will clear this up.

The reduction of H⁺ ions has a higher potential.

Note while they increase corrosion they reduce rusting.

 

[speersy]

i think he meant if the OH ions are used up in the neutralisation process with the acidic seawater, why does corrosion increase as even though more OH- are produced they are just used up again, but they are needed for corrosion.

I am puzzeled as well Barnzey don't worry.

EDIT: thanks xayma (jezz i type slow)

 

[Helga#2]

dosen't the rate of corrosion also have something to do with the depth of the water? at a certain depth the corrosion rate of metals increases signifficantly because of sulfur reducing bacteria. the bacteria use up the dissolved oxygen in the water and produce acidic bi-products.

 

[Skywalker]

There are a few ways you you can talk about this. The first one Xayma mentioned. The second one is that H+ can directly oxidise iron itself. The last one is that in the original equation (1/2 O2 + H20 + e- --> 2OH-), the presence of H+ will cause the formation of water and push equilibrium to the right, thus providing a path for electron transfer (and thus oxidation of iron).