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Q & A: Metals Affected By Acid

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Most recent answer: 10/22/2007
Q:
How do acids affect metal (reactivity)
- Sam (age 12)
Kennesaw, GA
A:
Sam:

I'm not entirely sure how to answer your question, so I'll approach it from several angles.

When you add a strong acid to a metal, you produce hydrogen gas and a compound with the acid anion and metal ion.

For example:

Mg + 2HCl -----> MgCl2 + H2

or

Na + H2SO4 ----> Na2SO4 + H2

The reaction is a so called oxidation-reduction reaction.

Magnesium is oxidized (loses electrons) to go from being in elemental form to that of the Mg+2 ion. (in MgCl2)

Hydrogen is reduced (gains electrons) to go from being H+ (in HCl) to Hydrogen gas.

The reactivity of the metal is reduced when acid is added. Elemental metals go from a more reactive uncombined form to a less reactive ionic form, generally speaking. (More so for the alkali and alkali earth metals than the transition metals)

Jason

(published on 10/22/2007)

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