Page 51 - Chemistry - XI

S. No. Test Observation Inference
2. Dry heating test

(a) Gas evolved (i) Colourless and odourless 2− indicated
CO
3
(ii) Colourless gas with rotten S indicated
2−
eggs
(iii) White fumes with suff ocating SO 2− indicated
smell 3
(iv) Yellowish green with Cl indicated
−
pungent smell
(v) Brown colour gas Br ,NO, NO may
−
−
−
3
be present 2
(vi) Purple of violet fumes I indicated
−
(vii) Vinegar like smell CH COO indicated
−
3
(b) Sublimate (i) White sublimate NH indicated
+
formation 4
(ii) Grey or black Hg salts
2+
(iii) Purple or black solid I indicated
−
(c) Decrepitation On heating Pb No or Ba NO

(crackling sound) 3 2 3 2
(d) Intumescence __ PO or Al +3
3−
(swells up) 4
(e) Colour of the (i) White when hot, blue when Cu +2 indicated
residue cold
(ii) Yellow when hot, white when Zn +2 indicated
cold
(iii) Blue when hot, pink when Co indicated
+2
cold
(iv) White residue glows on Mg or Al +3 indicated
+2
heating
(v) Reddish brown residue Fe or Fe indicated
+3
+2
(vi) Dark brown when hot and Pb +2 indicated
yellow when cold
(vii) Brown in hot and cold +2 indicated
Cd
(viii) Colour changes from green Ni indicated
+2
to yellow

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