Nail rusting

[sheasanchez]

My son did his project on nails rusting. Here is what he found
He used
1.Nail water and salt
2. Nail and sprite
3. Nail and OJ

The salt rusted the quickest why?
What should he look up for his research.

[donnahardy2]

Hi,

Rusting projects are a great introduction to chemistry for elementary students. It sounds like your son did a nicely controlled experiment and got the expected results, and now just needs to explain the science of his project.

Here is a website that explains the chemistry of rusting. It's an oxidation of solid iron (Fe) using an electrochemical reaction to form iron oxide. This process requires oxygen, water, and an electrolyte to facilitate the movement of ions.

http://www.corrosion-doctors.org/Experi ... mistry.htm

In your son's experiment, the salt (NaCl) provided the highest concentration of electrolytes to allow movement of the electrons from the solid iron to the oxygen atoms, so rust was able to form quickly. Salt is composed of sodium ions (Na) and chloride ions (Cl) that dissolve to made charged ions (Na+ and Cl-).

The orange juice was a good choice of solutions because acids also allow movement of the electrons, but the concentration of acid in orange juice must be lower than the concentration of the salt in the salt sample. Orange juice contains organic acids, which have a carboxyl group (COOH) that does not form charged ions (COO-) easily

Sprite contains mostly water and sugar. Sugar is a neutral, polar molecule and does not have a negative or positive charge. It can't conduct electricity, so rusting will be slower in a solution that doesn't allow movement of electrons.

I hope this helps. Please do let us know if you have any questions.

Donna Hardy

[sheasanchez]

Thank you that helps