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Systematic Qualitative Salt Analysis: Cation & Anion Detection

Experiment video

What you will learn

Systematically analyze an unknown inorganic salt to identify one acid radical (anion) and one basic radical (cation) through preliminary and confirmatory wet tests.

Materials needed

Unknown Inorganic Salt Sample (Lead Sulfate / Lead Nitrate) g
Unknown Inorganic Salt Sample (Lead Sulfate / Lead Nitrate) g
₹50
What is it?
Pure analytical reagent grade Lead Nitrate [Pb(NO3)2] test salt sample.
Specifications
Purity
≥ 99.0% AR grade
Heavy Metal
Standard group analysis reference
Physical State
White crystalline solid
Packaging
Polyethylene screw-cap bottle
Dilute and Concentrated HCl, H2SO4, and HNO3 set
Dilute and Concentrated HCl, H2SO4, and HNO3 set
₹95
What is it?
Set of diagnostic analytical chemical reagents in dropper bottles.
Specifications
Reagents
Dilute HCl (2M), BaCl2 (0.1M), KI (0.1M), K2CrO4 (0.1M)
Bottles
60 mL amber glass dropper bottles with vinyl teats
Purity
Reagent Grade
Barium Chloride (BaCl2) Solution mL
Barium Chloride (BaCl2) Solution mL
₹140
What is it?
Hard glass borosilicate test tubes and wooden test tube rack with peg drying stand.
Specifications
Tube Size
15 mm × 150 mm rimless culture tubes
Material
Borosilicate glass 3.3 thermal shock resistant
Rack
6-place polished hardwood rack with drying pins
Potassium Iodide (KI) Solution mL
Potassium Iodide (KI) Solution mL
₹185
What is it?
Standard laboratory apparatus used in Systematic Qualitative Salt Analysis: Cation & Anion Detection.
Specifications
Category
Chemistry Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard
Potassium Chromate (K2CrO4) Solution mL
Potassium Chromate (K2CrO4) Solution mL
₹230
What is it?
Standard laboratory apparatus used in Systematic Qualitative Salt Analysis: Cation & Anion Detection.
Specifications
Category
Chemistry Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard
Test Tubes with Stand, Test Tube Holder, & Boiling Tube set
Test Tubes with Stand, Test Tube Holder, & Boiling Tube set
₹275
What is it?
Standard laboratory apparatus used in Systematic Qualitative Salt Analysis: Cation & Anion Detection.
Specifications
Category
Chemistry Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard
Bunsen Burner & Platinum/Nichrome wire for flame test
Bunsen Burner & Platinum/Nichrome wire for flame test
₹320
What is it?
Standard laboratory apparatus used in Systematic Qualitative Salt Analysis: Cation & Anion Detection.
Specifications
Category
Chemistry Apparatus
Grade
CBSE / NEP 2020 Laboratory Standard

Tick items as you collect them. Tap + to see the product, specifications and buy options.

Stay safe

Always add concentrated acids dropwise along the inner wall of the test tube; never look down into the tube.
Never point the mouth of a heated boiling tube towards yourself or neighboring students.
Wash nichrome loop with conc. HCl until it produces no persistent color in the flame before testing.
Use clean test tubes rinsed with distilled water for confirmatory wet tests.

Steps

0 of 7 steps done

1Preliminary physical examination: record salt color, crystalline/amorphous state, and odor.
Observation
Record physical appearance: crystalline white powder without odor dissolves completely in warm distilled water.
Safety
Never taste laboratory chemicals; use clean spatula to handle salt crystals.
2Dry heating test: heat a pinch of salt in a dry test tube; observe decrepitation, sublimation, or gas evolution.
Observation
Treat salt with dilute H2SO4: no evolution of CO2, H2S, or NO2 gas eliminates Group 1 anions.
Safety
Point test tube mouth away from yourself and neighboring students.
3Flame test: prepare a paste with conc. HCl on a nichrome wire loop and introduce into non-luminous flame.
Observation
Add BaCl2 to salt solution: dense white precipitate of BaSO4 forms; remains insoluble in concentrated HCl.
Safety
Handle concentrated mineral acids in fume hood.
4Anion detection: test salt with dil. H2SO4 (carbonate/sulfite group), then conc. H2SO4 (chloride/nitrate group).
Observation
To original salt solution add dilute HCl: curdy white precipitate forms, indicating Group I cation (Pb²⁺).
Safety
Wash dropper immediately after transferring reagent.
5Wet test for sulfate: dissolve salt in water, add BaCl2 solution to obtain a thick white BaSO4 precipitate.
Observation
Boil white precipitate with distilled water and add KI solution: bright golden-yellow precipitate of PbI2 appears.
Safety
Use test tube holder while heating; boil gently without bumping.
6Prepare original solution (O.S.) for cation group separation: add dil. HCl to precipitate Group I (Pb²⁺ as white PbCl2).
Observation
Cool yellow solution under cold tap: breathtaking golden spangles crystallize and glitter under light.
Safety
Lead salts are toxic heavy metals; collect waste in designated heavy metal disposal bottle.
7Boil PbCl2 with water and divide: add KI solution to observe bright yellow PbI2 precipitation forming golden spangles upon cooling.

Tap + on a step to see what you will observe and any safety tips.

Record your observations

Test Performed	Experimental Procedure	Observation	Inference / Confirmation
Preliminary Physical	Color, state, odor, and solubility in water	White crystalline powder, odorless, soluble	Absence of Cu²⁺, Fe³⁺, Co²⁺, Ni²⁺; Salt is water soluble
Anion Dry Test	Salt + dilute H2SO4 in dry test tube	No brisk effervescence, no gas evolved	Absence of CO3²⁻, S²⁻, SO3²⁻, NO2⁻
Sulfate Confirmation	Salt solution + BaCl2 followed by dilute HCl	Dense white precipitate insoluble in conc. HCl	Confirms Sulfate ion (SO4²⁻)
Cation Group I Test	Salt solution + dilute HCl	White precipitate forms immediately	Group I cation present (Pb²⁺ indicated)
Lead Confirmation	Boil ppt in water, add Potassium Iodide (KI)	Brilliant golden yellow precipitate soluble in hot water, re-crystallizes as golden spangles	Confirms Lead cation (Pb²⁺)

Tap a highlighted cell to write your own observation.

Result and conclusion

Anion confirmed as Sulfate (SO4²⁻) via white BaSO4 precipitate insoluble in conc. HCl. Cation confirmed as Lead (Pb²⁺) via golden yellow PbI2 spangles test.

Pb(NO3)2 + 2 KI -> PbI2↓ (Golden Yellow Spangles) + 2 KNO3; BaCl2 + SO4²⁻ -> BaSO4↓ (White ppt)

Observation	What it means
Group I Cation Confirmed	Formation of white PbCl2 precipitate upon adding dilute HCl confirms Group I basic radical (Lead, Pb²⁺).
Golden Spangles Reaction	Pb²⁺ reaction with KI produces PbI2 which dissolves on boiling and crystallizes upon cooling as shimmering golden-yellow spangles.
Sulfate Anion Confirmed	Formation of white BaSO4 precipitate that remains insoluble even in concentrated boiling HCl confirms sulfate (SO4²⁻).
Systematic Identification	The given inorganic salt is conclusively identified as Lead Sulfate / Lead Nitrate [Pb²⁺ and SO4²⁻ / NO3⁻].

Solubility of Lead Iodide (PbI2) in Water vs Temperature

Sample readings. Replace with your own results.

Experiment photos

Before the experimentDuring the experimentResult