This chapter is aimed at providing researchers with enough information when making research anlysis.
: Qualitative Analysis for Identification of Metal Cations
There are two points as the aims of this experiment: (1) To identify protein by using peptide bond at protein through biuret test, sulfur test, precipitate by metal, precipitate by salt and protein...Full description
Guide for salt analysis for XII studentsFull description
QUALITATIVE ANALYSIS OF INORGANIC SALT
(Acidic Radicals) PRILIMINARY TESTS
No .
Test
Observation
1.
Colour
Blue or bluish green
Cu +2 may be present
Light green
Fe +2 may be present
Dark bro wn
Fe +3 may be present
Green
Ni+2 may be present
Pink
Co+2 may be present
Inference
Shows the absence of the above radicals
White
2.
3.
Odour
Deliquescence
Ammonical smell
NH 4+ may be present
Vinegar like smell
CH 3CO O - may be present
Salt absorbs moisture and becomes paste like.
1. If coloured, it may be Cu(NO 3) 2 , FeCl3. 2. If colourless, it may be Zn(NO3) 2,Chlorides of Zn+2,Mg +2 etc.
IDENTIFICATION OF ACID RADICALS (WET TESTS )
No .
Test
Observation
1.
Test for CO 3-2 :
Brisk effervescence (CO 2 gas) gas)
Salt + dil. H2S O 4 (2 ml)
Reaction:
Inference
CO 3-2 + H 2SO 4
CO3-2 may be present
S O 4-2 + H 2O + CO2
CT for CO 3-2 Salt + dil. HCl Brisk effervescence & evolution of CO 2 gas Observation: Brisk Reaction:
2.
CO 3-2 + HCl
Cl - + H 2O + CO2
CO3-2 is confirmed
Test for Cl-, Br- & N O 3-:
Colourless gas (HCl) with pungent smell, white fumes (of NH4Cl (s))
Salt + conc. H 2S O 4 (2 ml)
with aqueous NH 4OH. [HCl + NH 4OH
Cl - may be present
NH 4Cl (s) + H 2O(l)]
Reaction:
Cl - + H 2S O 4
HC I(g)+ HSO 4-
Reddish brown gas with pungent smell.
Br- may be present.
It does not turns FeSO 4 solution black. Reaction s:
Br- + H 2SO 4 2HBr + H 2SO 4
HS O 4- + HBr
Br2(g) + SO2(g) + 2H 2O
Important Note: If no brown fumes are observed, add one Cu chip
NO 3- may be present.
and heat. Reddish brown gas (NO 2) with pungent odour, odour, turns FeSO 4 solution
black. ion s: React ion
NO 3- + H 2S O 4 4HNO3 + C (paper pellet)
HNO 3 + HSO44NO 2
+ CO2 + 2H 2O
(brown gas)
No gas / vapo ur evolved
the above radicals are
absent.(go for independent radical tests i.e.SO 4-2 & PO 4-3)
1
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CT for Cl Salt + water + AgNO 3 solution (2-3 drops) Observation: White ppt.is formed which is soluble in ammonium hydroxide Reaction:
Cl - + AgNO3
+ N O3-
Ag C l
Cl - is confirmed.
CT for Br Salt + water + AgNO 3 solution. (2- 3 drops) Observation: A light yellow ppt.( AgBr (s) ) is obtained which is partially soluble in NH 4OH(aq).
Br-(aq) + AgNO3(aq)
Reaction:
AgBr
NO3-(aq)
+
Br- is confirmed.
(light yellow ppt.) CT for NO 31.
Salt + Water + Diphenyl amine (5(5 - 7 drops)
Observation: Deep blue colouration. Reaction:
2. Ring
NO 3- + H 2S O 4
test: Salt + water +
H 2C2O4 + HSO4-
NO 3- is confirmed.
FeSO 4 solution (1ml -freshly prepared) + few drops of conc.H 2SO 4 along the side of the test- tube.
Observation:
Formation of brown ring at the junction of two liquids Reaction:
NO 3- + H 2SO 4
HS O 4- + HNO 3
6FeSO 4 + 3 H 2S O 4
3Fe 2(S O 4) 3 + 4H 2O + 2NO NO 3- is confirmed.
[Fe (NO)( H 2O)5]SO4
FeSO 4 + NO + 5H 2O
(Brown ring)
2.
Test for SO 4-2 : Salt +
White ppt.( BaSO4) insoluble in dil. HCl
water + BaCl 2(aq)
actions: Re actions:
S O 4-2 + BaCl2
BaSO 4
S O 4-2 may be present
+ Cl -
CT for SO 4-2 : Lead Acetate test: Salt + Water + (CH 3COO)2Pb(aq) Observation: White Observation: White ppt. of PbSO 4 Reaction:
4
S O 4 -2 + (CH 3COO)2Pb(aq)
PbSO 4
Test for PO 4-3 (as well
Deep yellow ppt
as CT):
Reactions:
Am mo. M olybdate test Salt + water + conc. HNO3 + boil +
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