Preliminary test for finding salt anions.

Question

Preliminary test for finding salt anions.

Answer 1

1) add a few drops of  0.1 M AgNO3 to the sample slightly acidified with HNO3 :

this ppt's Chloride, Bromide, iodide & sulfide

2) add a few drops of 0.1M Ba Cl2 to a neutral sample:

this ppt's sulfate, sulfite, carbonate, phosphate, borate, arsenate..

3) add concentrated H2SO4 to the dry sample:

a gas is evolved from nitrite (red-brown gas), carbonate, sullfide (rotten egg gas), sulfite (burnt sulfur gas)

4) if no nitrite, roast the the dry crystal in a test tube over an open flame:

and a brown gas is evolved from nitrates