Practical No. 02: Identification of Anions
XIII. Interpretation of Results
Qualitative anion analysis successfully identified acidic radicals using group reagents. Gas evolution, coloured precipitates, and specific colour changes confirmed the presence of respective anions in the sample solutions.
XIV. Conclusions and Recommendations
- Conclusion: Systematic anion analysis with group reagents effectively identifies acidic radicals.
- Recommendation: Use freshly prepared reagents, avoid contamination, and perform tests in proper sequence for accurate results.
XV. Practical Related Questions & Answers
Q1. Identify the acidic radical in solution ‘A’ by observing the release of CO₂ gas upon reacting with diluted nitric acid (HNO₃).
- Answer: The acidic radical is CO₃²⁻ (Carbonate). When carbonate reacts with dilute HNO₃, it liberates CO₂ gas which turns lime water milky due to formation of CaCO₃. The effervescence observed confirms the presence of carbonate ion.
Q2. Write the procedure for separating halides in a sample solution through a separation test.
- Answer: To separate halides, add dilute HNO₃ followed by AgNO₃ solution. White precipitate indicates Cl⁻, pale yellow precipitate indicates Br⁻, and yellow precipitate indicates I⁻.
- Confirmation: For further confirmation, add chloroform and chlorine water — chlorine water liberates halogens which dissolve in chloroform giving characteristic colours: Cl⁻ gives colourless layer, Br⁻ gives yellowish brown layer, and I⁻ gives violet layer.
Q3. Identify the anion in solution ‘X’ when mixed with barium nitrate which gives white ppt.
- Answer: The anion is SO₄²⁻ (Sulphate). Barium nitrate gives a white precipitate of BaSO₄ which is insoluble in dilute HNO₃. This confirms the presence of sulphate ion. The confirmatory test can also be performed using BaCl₂ solution which gives the same white precipitate.
Leave a Reply