why is salt corrosive?

Question

anything to do with the relationship between salt and corrosion would help.
actually anything to do with the salt would help
same goes for corrosion.

Answer 1

Salt in the presence of moisture is corrosive because both sodium and chloride ions are highly reactive.

Answer 2

Lancenigo di Villorba (TV), Italy

I think you refer to "Wet Corrosion Phenomena" of Iron and Mild Steels.
In the latter half of XX century, scientists overcame a mechanism explicating the some chemical corrosion of iron-based matters put in moist surroundings.
An interesting mechanism is "Pit Corrosion".
The CLOSEST AREAS OF THE IRON-BASED DEVICES takes part on the following Anodic Half-Reaction :

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

in assignement an Anodic Role to the overdefined CLOSEST AREAS, e.g. the scratches, the grooves, the covered parts.
In this manner, the ferrous ions join in the aqueous media neighbouring the metal, where they stay.
Here, these ions act in a manner trending to form its hydroxide

Fe++(aq) + 2 H2O(aq) ---> Fe(OH)2(s) + 2 H+(aq)

leading to increasing hydrogen ion's concentrations. The greater the hydrogen ion's concentration, the greater the ferrous ion's one because runs the Cathodic Half-Reaction coupled (e.g. it takes part on the FREE AREAS) with the Anodic one :

4 H+(aq) + O2(g) + 4e ---> 2 H2O(aq)

You seen! VERY LATELY a self-feeded mechanism starts and its rate increases and increase and so on.

WHAT DOES SALT DO?
Kitchen salt's solutions (e.g. NaCl) or brine's ones play a VERY IMPORTANT ROLE in the mechanism's promotion. While the reaction destroy the iron-matters, chloride ions act as
counter-ions diffusing in the growing groove in a manner to balance the electrical charge.

CONCLUSIONS
"Pit Corrosion" interests a very common type of Iron-based matters in moist surrounding. Several steps built its mechanism, among those several ones are depending on the basis of ion's diffusion rates. Chloride ions of kitchen salt act favouring these diffusion events and they begin an important promotion of the mechanism.

I hope this helps you.

Answer 3

Because it is basic salt.

Any Acid or basic salt is corrosive