Analysis of Group 1 Cation | Lead Cation | Confirmatory Test of Lead | Salt Analysis | Class 11 & 12

Introduction

This tutorial provides a step-by-step guide on the analysis of Group 1 cations, specifically focusing on lead cation and its confirmatory tests. Understanding these concepts is essential for students in Class 11 and 12 studying chemistry, as they form the basis for salt analysis and qualitative analysis of ions.

Step 1: Understanding Group 1 Cations

Group 1 cations include lead (Pb²⁺), silver (Ag⁺), and mercury (Hg²⁺). These cations are typically analyzed together due to their similar chemical properties.

• Key Properties:

  • All are positively charged ions (cations).
  • They form insoluble chlorides.

• Common Sources:

  • Lead can be found in compounds such as lead acetate or lead nitrate.

Step 2: Preparing for Lead Cation Analysis

Before conducting any tests, gather the necessary materials and set up a safe working environment.

• Materials Needed:

  • Test tubes
  • Bunsen burner
  • Reagents: hydrochloric acid (HCl), ammonium sulfide ((NH₄)₂S)
  • Distilled water
  • Safety gear: goggles, gloves, lab coat

• Safety Precautions:

  • Always wear safety goggles and gloves.
  • Work in a well-ventilated area or under a fume hood.

Step 3: Conducting the Preliminary Test for Lead

To identify the presence of lead, perform a preliminary test.

1. Dissolve the Sample:

   • Take a small amount of the salt sample and dissolve it in distilled water in a test tube.

2. Add HCl:

   • Add a few drops of hydrochloric acid to the solution.
   • Observe for the formation of a white precipitate, which indicates the presence of lead ions.

Step 4: Confirmatory Test for Lead Cation

Once you suspect lead is present, conduct a confirmatory test to verify.

1. Add Ammonium Sulfide:

   • To the solution containing lead ions, add a few drops of ammonium sulfide.
   • A black precipitate indicates the presence of lead ions.

2. Confirm the Result:

   • Filter the precipitate and wash it with distilled water.
   • The black precipitate is lead sulfide (PbS).

Step 5: Analyzing the Results

After conducting the tests, analyze your findings.

• Interpretation:

  • A white precipitate with HCl suggests the presence of lead.
  • A black precipitate with ammonium sulfide confirms lead ions.

• Documentation:

  • Record your observations, including color changes and precipitate formation.

Conclusion

In this tutorial, you learned how to analyze Group 1 cations with a focus on lead cation. The key steps included understanding group characteristics, preparing for analysis, conducting preliminary and confirmatory tests, and interpreting results. For further study, consider exploring tests for other cations in Group 1 and their applications in different fields, such as environmental science and material analysis.