[slayer]

Hello all, this is my first post on the forums.

I am supposed to describe one qualitative analysis test that could be performed to identify that an unknown is Hydrochloric Acid.

I thought about it, and assumed that if perhaps a piece of chalk (CaCO3) could be dropped into an HCl solution and if it dissolved, the solution could be deemed as HCl.

But on a side note, as HCl dissolves insoluble carbonates, such as calcium carbonate, Im almost certain that HNO3 dissolves them as well. So how could they be told apart?

So my questions are as follows:
1)How would I formally describe a "qualitative analysis test"?
 
2) How can I identify HCl or HNO3?

thanks

[Borek]

IMHO you need two tests - one to identify it is acid, one to identify Cl^-. Do you know of any insoluble chlorides, that will precipitate when added to HCl solution?

[slayer]

potassium chloride!

[slayer]

So for HCl and HNO3..

Calcium carbonate could be used to identify both the acids

potassium+ ion can be used as an aqueous solution to identify HCl when it precipitates KCl(s).

Sodium+ ion can be used as an aqueous solution to identify HNO3 when it pecipitates NaNO3(s)


does this sound correct?

[Borek]

does this sound correct?

I am afraid not. Where did you get the information about KCl and NaNO₃ insolubility? Google solubility rules.

[mdlhvn]

So my questions are as follows:
1)How would I formally describe a "qualitative analysis test"?
 
2) How can I identify HCl or HNO3?

1) You have to describe the chemical used, the operation and the phenomenon happened. For example, add some CaCO3 to the solution, if the solid dissolves and some bubbles appear, it means the solution comprises of ion H+

2) It is very simple, as Borek said. You should find it in the solubility table in periodic table.

Good luck