how to find halogens?

Question

You suspect that your unknown contains halogen, so you perform the silver nitrate in ethanol test and the sodium iodide in acetone test, both of which are negative. Do these results prove that your compound does not contain halogen? Briefly explain.

Answer 1

Not necessarily.

They only prove that the unknown does not contain halide ions. Halogens may be present in other groups.

Answer 2

If were hexachlorobenzene, what would you have seen in each case?

You do the Beilstein test. A clean copper wire is heated in a flame so no color comes off. Immediately touch to a bit of your sample. Sizzle! Back into the flame. If there is a colored flare your sampel has halogen. Fluorine gives a yellowish flare, other halogens green to blue.

You do a sodium fusion and then a silver nitrate test.

Answer 3

Hi
i will help u out...
-===========================================
According to me,halides are PRESENT but in other groups........
========================================
POSSIBLE MISTAKES U HAVE MADE ??

1) Used Excess of chemicals...in salt analysis...

2) i also used to find after doing these tests absence of halogens...but they r always there...!!

==========================================
SUGGESTIONS....FOR U..!!

1) If silver nitrate test doesnt work....!!

......Go for Chromyl Chloride Test for Chlorine radical...!!

Take a mixture of..salt and K2Cr2O7 (ratio 1:3) To this add conc. H2So4..brown vapours come up..collect it in a test tube with NaOH ...then add Lead Acetate...YELLOW PPT..

...Go for Layer test in case of bromide or iodide radical..

Add Carbon Tetra Chloride to th salt ..add Chlorinated water..to the mxture...

for Bromine == A brown layer is formed
for Iodine == A violet layer is formed...

==========================================

Hope this is the best answer,uve got,..
all the best

Answer 4

if silver nitrate is added in any of the solution which contains a halogen, then a precipitate is appeared the colour of which depends upon the halogen
F in very reactive it can even react with the test tube
in the presence of Cl, white precipitate
in the presence of Br, cream precipitate
in the presence of I, yellow precipitate