Design an experiment to determine which reactant is the limiting reactant

[extraordinarygirl]

You have a piece of Mg of an unknown mass, and a beaker of water in which is dissolved an unknown amount of HCl. Design an experiment to determine which reactant is the limiting reactant.

I'm not too sure how to get started with this problem. I was thinking you could place the magnesium into the beaker of H20 and HCl and see if the magnesium dissolves at all. If all of it dissolves than the Magnesium would be the limiting reactant... but if not all of it dissolved HCl would be the limiting reactant
- Can anyone tell me if I am on the right track?

 

[extraordinarygirl]

Can anyone give me an idea?

 

[Ouabache]

Just wondering, what kind of products do you expect to result? What are some other clues that would indicate a reaction is taking place?
Sounds like you thought this through.. I go along with your approach..

 

[Pengwuino]

Write out the chemical equation and see what the products will be. I have a feeling that an indirect measurement will be of better use... but I'm not sure.

 

[Cesium]

If all of it dissolves than the Magnesium would be the limiting reactant... but if not all of it dissolved HCl would be the limiting reactant

That's perfectly logical and all you would need to do, assuming of course the reaction goes to completion (which it will over time).

 

[Ouabache]

That's perfectly logical and all you would need to do, assuming of course the reaction goes to completion (which it will over time).

There is an implication here in Cesium's comment about rate of reaction. Do you know what it is? (query is for ExGrl)