Question

Why does water cause rust?

Answer 1

Rust:

Wasting away of iron due to the presence of air and moisture and the formation of oxide is termed “rust”.

$\mathrm{Fe}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)+\mathrm{x}.{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to \underset{\left(\mathrm{Rust}\right)}{\underbrace{{\mathrm{Fe}}_2{\mathrm{O}}_3.{\mathrm{xH}}_2\mathrm{O}}}$

• When ferrous metals corrode, the term "rust" refers to the red iron oxides that develop.
• When iron combines with oxygen and water, the resultant compounds are known as rust.

Water rusting:

• Iron oxide, sometimes known as rust, is formed when the iron is exposed to oxygen and moisture over an extended length of time.
• Over time, the oxygen reacts with the metal at the atomic level, generating an oxide.
• When iron oxidizes, rust is formed. Water is the primary catalyst in the rusting process.
• When metals interact with oxygen to generate metal oxides, corrosion takes place naturally.
• All water is somewhat corrosive because it has some dissolved oxygen in it.
• The pH, electrical conductivity, oxygen concentration, and temperature of the water are only a few of the variables that affect corrosion rate.