17_18_46_9_08_2024_Qualitative Analysis-1
Chemistry Notes
Page 1
Qualitative Analysis
Involves detecting cations and anions in salts or mixtures.
Physical Examination of the Mixture
Observations and Inferences
Color
Blue or bluish green: Cu2+ or Ni2+
Greenish: Ni2+
Light green: Fe2+
Dark brown: Fe3+
Pink violet: Co2+
Light pink, flesh color, or dull earthy color: Mn2+
Smell
Ammonical smell: NH4+
Vinegar-like smell: CH3COO–
Rotten eggs smell: S2–
Density
Heavy: Salt of Pb2+ or Ba2+
Light fluffy powder: CO3 2–
Deliquescence
Salt absorbs moisture and becomes paste-like.
Page 2
Dry Heating Test
Observations and Inferences
Gas Evolved
Sublimate Formed
Decrepitation
Fusion
Swelling
Residue
Page 3
Detection of Gas Evolved
Charcoal Cavity Test
Cobalt Nitrate Test
Page 4
Flame Test
Color of Flame
Borax Bead Test
Page 5
Color in oxidizing and reducing flames
Solubility Chart
Page 6
Analysis of Anions (Acidic Radicals)
Group 'A' Radicals with observations and inferences
Page 7
Concentrated Sulphuric Acid Group
Group 'B' Radicals with precipitation reactions and oxidation/reduction in solutions
Page 8
Preparation of Sodium Carbonate Extract
Individual tests for Group 'A' Radicals like carbonate ion and sulphite ion
Page 9
Continued tests for sulphide ion
Page 10
Tests for nitrite ion and acetate ion
Page 11
Test common to halides Cl–, Br–, I–
Action of heat on halides, specifically chloride ion
These notes cover various qualitative analysis tests for detecting cations and anions in salts or mixtures, including observations, inferences, and specific tests for different ions.
Chemistry Notes
Page 12
Qualitative Analysis of Bromide Ion (Br¯)
Reactions involving Bromide Ion:
Formation of precipitate
Formation of gas
Other reactions with specific reagents
Page 13
Chemistry of Iodide Ion (I¯) and Nitrate Ion (NO3¯)
Iodide Ion reactions:
Formation of precipitate
Other specific reactions
Nitrate Ion reactions:
Formation of precipitate
Additional reactions with reagents
Page 14
Qualitative Analysis Continued
Action of Heat:
Reactions under gentle warming
Group of anions not reacting with H2SO4 but giving precipitates with certain reagents
Sulphate Ion (SO4 2–) reactions:
Reactions with dilute and concentrated H2SO4
Precipitation reactions with specific reagents
Page 15
Chemistry of Phosphate Ion (PO4 3–) and Borate Ion (BO3 3–)
Phosphate Ion reactions:
Formation of precipitate
Borate Ion reactions:
Specific reactions mentioned
Page 18
Qualitative Analysis Lecture II: Analysis of Cations (Basic Radicals)
Note:
Details about groups, reagents, and precipitate colors for cation analysis.
Chemistry Notes
Page 19
Analysis of Cations
Group 1st radical (Ag+, Pb2+, Hg22+) precipitated as chloride due to low solubility product.
Hydroxides do not precipitate in acidic medium.
Group 2nd radical precipitated as sulphide due to low solubility.
Group 4th cations precipitated with ammonium hydroxide.
Use of HCl to decrease S2- concentration.
Avoid using H2SO4 instead of HCl.
Original Solution Preparation
Used for basic radical analysis except NH4+.
Prepared by dissolving salt in suitable solvent.
NH4Cl suppresses ionization for group 3 cations precipitation.
Differentiation between soluble and insoluble salts/mixtures.
Sequential dissolution in H2O, dil. HCl, and conc. HCl based on solubility.
Boiling off H2S in 2nd to 3rd group transition.
Oxidation of Fe2+ to Fe+3 in the original solution.
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Qualitative Analysis
Detection of Ammonium Ion (NH4+) using Sodium Hydroxide Solution.
Tests involving Nessler's Reagent, Sodium Hexanitritocobaltate (III) Solution, etc.
Initial focus on 1st group cations (Pb2+, Hg22+, Ag+).
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Lead Ion (Pb+2)
Precipitation reactions for lead ion.
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Mercury Ion (Hg2 2+) and Silver Ion (Ag+)
Precipitation reactions for mercury and silver ions.
Chemistry Notes
Page 23
IInd Group: Hg2+, Pb2+, Bi3+, Cu2+, Cd2+, As3+, Sb3+, Sn2+
IIA Group: Hg2+, Pb2+, Bi3+, Cu2+, Cd2+
Page 24
Mercury Ion (Hg2+)
Series of reactions involving H+ ions and precipitation
Copper Ion (Cu+2)
Involves heat in the reaction
Page 25
Bismuth Ion (Bi+3)
Reactions leading to precipitation
Cadmium Ion (Cd+2)
Series of reactions
Page 26
Lead Ion (Pb2+)
Precipitation reactions
IIB Group: As3+, Sb3+, Sn2+, Sn4+
Page 27
Arsenic Ion (As+3)
Involves heat in the reaction
Antimony Ion (Sb+3)
Series of reactions
Tin (II) Ion (Sn+2) and Tin (IV) Ion (Sn+4)
Precipitation reactions
Page 28
Sn
Reactions leading to precipitation
IIIrd Group: Al+3, Cr+3, Fe+3
Page 29
Aluminimum Ion (Al3+)
Reactions with NH4Cl leading to precipitation
Iron Ion (Fe3+)
Involves heat in the reaction
Page 30
Series of reactions involving different ions
Important Note: Specific reactions mentioned
Page 31
Chromium Ion (Cr3+)
Series of reactions involving CH3OOH and amyl alcohol
Chemistry Notes
Page 32
Qualitative Analysis of IVth Group (Zn+2, Mn+2, Ni+2, Co+2)
Manganese Ion (Mn2+):
Precipitation reactions indicated by arrows.
Specific reactions leading to precipitation or not.
Page 33
Zinc Ion (Zn2+)
Behavior in neutral solutions.
Partial precipitation with specific reactions.
Formation of complexes indicated by arrows.
Page 34
Qualitative Analysis of Cobalt Ion (Co2+)
Reactions involving NH4OH.
Precipitation or non-precipitation indicated.
Formation of complexes and specific reactions shown.
Page 35
Nickel Ion (Ni2+)
Reactions with NH4OH.
Formation of complexes and precipitation.
Specific reactions leading to different outcomes.
Page 36
Qualitative Analysis of Vth Group (Ba2+, Sr2+, Ca2+)
Barium Ion (Ba2+):
Specific reactions leading to precipitation or not.
Strontium Ion (Sr2+):
Reactions and outcomes shown.
Calcium Ion (Ca2+)
Example reactions and outcomes.
Magnesium Ion (Mg2+)