[stormblessed]

Task: To determine the identity of an unknown substance using qualitative and quantitative tests.

After conducting some qualitative tests, I have narrowed down the identity of the unknown substance (clear colourless liquid) to either HCl or HBr. Tomorrow, we are conducting quantitative tests in class and I am unsure of what tests to do and/or how to differentiate between HBr and HCl. What are some quantitative tests that would allow me to determine the identity of the substance? I am thinking of titration, but I don't know how that would allow me to narrow it down to one of the two.

Thanks

[Borek]

Determining molar mass of the anion should be a killer here.

[stormblessed]

What tests can I perform to calculate that? I understand how that would be helpful but I don't know what tests to do.

[Borek]

Think in terms of precipitation.

[stormblessed]

I have no idea. Plus, we do not have any more time to perform any qualitative tests (including PPT reactions), so I wouldn't be able to do any precipitation reactions.

[Borek]

Precipitation is not only a qualitative test, it is also a basis of the quantitative method called gravimetric analysis.

[snorkack]

Easily precipitating salts of Cl and Br (and I) are those of Ag, Tl, Pb and Hg.
Which of them is likely to give an easy, dry precipitate, so you weigh a solid and not enclosed water?
Or would any of them have a nice way to detect endpoint of titration?