Chemistry: Reactions between metals and non-metals.

[calpol09]

Hi guys,
I'm doing a write-up on whether or not the type of carboxylic acid affects its rate of reaction with magnesium powder.
Chemistry is far from my best subject...
Could anyone give me a hand with the balanced equations for:

Benzoic Acid +Magnesium
C6H5COOH +Mg

Tartaric Acid +Magnesium
C4H6O6 + Mg

Citric Acid + Magnesium
C6H8O7 + Mg

Would really appreciate the hand
Thanks x

[moneyfaery]

[quote name='calpol09' post='34226' date='Jan 21 2009, 04:38 PM']Benzoic Acid +Magnesium
C6H5COOH +Mg

Tartaric Acid +Magnesium
C4H6O6 + Mg

Citric Acid + Magnesium
C6H8O7 + Mg[/quote]
Hydrogen gas should be produced from the acid + metal reactions. So taking a wild guess:

1. MgC[sub]6[/sub]H[sub]4[/sub]COO + H[sub]2[/sub]
2. MgC[sub]4[/sub]H[sub]4[/sub]O[sub]6[/sub] + H[sub]2[/sub]
3. MgC[sub]6[/sub]H[sub]6[/sub]O[sub]7[/sub] + H[sub]2[/sub]

[ezex]

look, it's very hard to tell what magnesium will do to these compounds because 1) you didn't exactly give us any reagents and 2) magnesium and all of the other metals behave oddly and the best way to test them is by doing an actual experiment. Here's what little theory I can apply to this scenario:

The simplest reaction would be the Sn2 that Irene mentioned. Unfortunatel, it is very unlikely that magnesium will replace a hydrogen given its very low electronegativity. For this reaction to happen, however, you might want to apply light or heat. By doing this you would create a radical which would in turn replace an Mg from an Mg2 molecule with a hydrogen.

But what this truly looks like is a perfect example of Grignard Reactions. It's very interesting to look into these reactions because they are remarkable. They involve changing things like benzoic acid into alkylhalydes with the extra alkyl group containing Magnisium. The hydroxy group is the one that generally gets replaced which is why i'm mentioning Grignards but look into it a little more to get a better idea.