Title: Step-by-Step Qualitative Analysis of Strontium Chloride (SrCl₂)
Introduction
Strontium chloride (SrCl₂) is a water-soluble ionic compound commonly used in laboratory testing and chemical analysis. This document outlines the qualitative analysis of SrCl₂ to identify its cation (Sr²⁺) and anion (Cl⁻) through systematic tests.
Step-by-Step Analysis of SrCl₂
1. Preliminary Examination
Property
Observation
Physical Appearance
White crystalline solid
Solubility
Soluble in water, forming a colorless solution
Odor
Odorless
2. Dry Heating Test
Procedure
Observation
Inference
Chemical Equation
Heat a small sample in a dry test tube.
No decomposition or characteristic odor observed.
Indicates stability of SrCl₂ at moderate temperatures.
No reaction
3. Flame Test
Procedure
Observation
Inference
A platinum wire is dipped in SrCl₂ solution and introduced to a non-luminous flame.
Crimson red flame is observed.
Confirms the presence of Sr²⁺ ions.
4. Identification of Strontium (Sr²⁺) Ion
Test
Reagent Used
Observation
Inference
Chemical Equation
Sulfuric Acid (H₂SO₄) test
Dilute H₂SO₄ solution
White precipitate
Confirms Sr²⁺ presence
Sr²⁺ + SO₄²⁻ → SrSO₄ (white ppt.)
Ammonium Carbonate ((NH₄)₂CO₃) test
(NH₄)₂CO₃ solution
White precipitate
Confirms Sr²⁺ presence
Sr²⁺ + CO₃²⁻ → SrCO₃ (white ppt.)
5. Identification of Chloride (Cl⁻) Ion
Test
Reagent Used
Observation
Inference
Chemical Equation
Silver Nitrate (AgNO₃) test
AgNO₃ solution
White precipitate, soluble in NH₄OH
Confirms Cl⁻ presence
Cl⁻ + Ag⁺ → AgCl (white ppt.)
Conc. Sulfuric Acid (H₂SO₄) test
Conc. H₂SO₄ + heat
Dense white fumes of HCl gas
Confirms Cl⁻ presence
SrCl₂ + H₂SO₄ → SrSO₄ + 2HCl (gas)
6. Group Analysis of Sr²⁺ (Cation Analysis)
Strontium ion (Sr²⁺) belongs to Group V in cation analysis, which includes Ba²⁺, Sr²⁺, and Ca²⁺. The group reagent used for its identification is ammonium carbonate ((NH₄)₂CO₃) in the presence of ammonium chloride (NH₄Cl) and ammonia (NH₄OH).
Test
Reagent Used
Observation
Inference
Chemical Equation
Group Precipitation
(NH₄)₂CO₃ in presence of NH₄Cl and NH₄OH
White precipitate
Confirms Sr²⁺ presence
Sr²⁺ + CO₃²⁻ → SrCO₃ (white ppt.)
Flame Test
Platinum wire in non-luminous flame
Crimson red flame
Confirms Sr²⁺
Sr²⁺ produces a characteristic flame color
Conclusion
The qualitative analysis of SrCl₂ confirms the presence of strontium (Sr²⁺) and chloride (Cl⁻) ions through distinct chemical reactions, solubility tests, and confirmatory tests.