factor affecting rusting

Question

From my chemical book,it said that acid solution or sea water are electrocyte so it can increase the electrical conductivity ann then speed up rusting.However,why an increase in electrical conductivity of iron can spped up rusting?

Answer 1

Acid solution or sea water are electrocytes so it can increase electrical conductivity.

According to the first equation of rust (should be found in your textbook)

Fe-->Fe2+ + 2e-

So iron LOSES ELECTRONS first for rusting to occur.

Increasing in electrical conductivity will increase iron's tendency to lose electrons, so it will rust more quickly.


Something more:
Electrical protection by connecting to a negative terminal of a car works using this same principle. The negative terminal SUPPLIES ELECTRONS to the iron, preventing it to rust.

Also, sacrificial protection works in the same way. The metal higher in the reactivity series (e.g. zinc) loses electrons preferrably than iron. So iron is protected.


Hope I can help you!!!!