Thread: identifying anions and cations

Hi there

I was wondering if someone could give me a description of how the tests that you use to identify anions and cations actually works

I did this experiment at college but don't know it actually works lol

Could you elaborate? What kind of tests?

I think we conducted tests to identify unknown inorganic compounds using anion and cation tests.

First we put some solution into a beaker, then put some indicating solution to it so it changed colour, then we put another solution in it until it changes to colourless


....something like that

I wanted to know how these tests work.

here's a link to what we did

http://students.ed.uiuc.edu/bwwolfe/...20ion%20id.doc

[quote="keraky"]Hi there

umm I did exactly the same thing in college and iv got an assignmet asking me to identify how the compounds work.
but i dont know

When you add silver nitrate to the cl- ions the nitrate is displaced and the result silver chloride precipitate which is a creamy white I believe.
When you add barium chloride to sulphate ions the sulphate ions displace the chlorine and because the sulphates of group II metals decrease in solubility down the group a white precipitate is formed.

Not sure about this one but if I were to guess: different elements give off different wavelengths of light when heated due to electrons changing from different subshells.

For the ammonium ion one all I can think of is that the adding of sodium hydroxide lowers the pH by combining to form water

Thats all I know, hope it helps