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What does saltwater have that rusts iron nails

I need to know what saltwater has that rusts iron nails because its for a science project.

Mattew L.
student - Canada
2005

The clue is in the question, salt - water, add a little oxygen and voila!

Brian Terry
Aerospace - Yeovil, Somerset, UK
2005

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The thing in saltwater that makes it corrosive to nails is the salt. The salt has sodium and chloride in it; chloride ions are really aggressive towards many metals. To make things go even faster, you also need a good dose of oxygen to promote the rusting process.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2005

Simply chloride ion.

JAMAL
- India
2005

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so why does a nail in vinegar ⇦in bulk on eBay or Amazon [affil links] rust more than the nail in salt water, if salt water accelerates oxidation?

Erika R
- Los angeles, california
August 6, 2010

Hi, Erika
Yes, you can add salt to water to accelerate corrosion, but everything is relative. You can put a turbocharger on a Prius for better acceleration, but it's still not going to outrun a Ferrari. Salt water is more corrosive than fresh water, but vinegar is an acid and is much more corrosive to metal than salt water.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey