Why might flame tests sometimes be invalid?

Question

please help me.

Answer 1

Flame tests need to be very accurately done, slightest of mistakes and the test doesn't give you results even if you are right..........

Also, adulterated chemicals are used in colege labs, that is also a reason why tests fail........dont be soooo sad dear.....

Answer 2

there are some elements whose flame tests are nearly the same
for example Mn, Mo has yellowish green flame test , Pb,Sb has pale green.
Another problem is that if someone lacks of ability to determine the difference between the two flame tests, he can't determine the substances well

Answer 3

Lancenigo di Villorba (TV), Italy

You read answers which preceed mine.
You unsterstood not all cations can emits visible light owing its energetic eccitation for flame's exposure.
On the topics, I remember you that you must dose analyte with HCl's strong solution for chloride's salts in situ creation.
Among known compounds, chlorides usually show greatest sublimation, so you try obtain chlorides compound of unknown cations.
But, as you know, some chloride salts are "very heavy".
Can Ag(I) or Pb(II) influence burner's flame? Not, they can't.

I hope this helps you.

Answer 4

flame test is based on eletronic cocept as when energy is gained by the eletron[e-] then they reach higher energy level so are unstble when they lose their energy in tyhe form of visible colours flame test comes to b positive but in some cases electron dont get so much of energy so show negative test okayyyyyyy!!!!