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Qualitative Analysis

 
6.11 Qualitative Analysis
 
Qualitative Analysis of a Salt 
A technique used to identify the cation and anion present in a salt by analysing its physical and chemical properties.
 
The image is an infographic titled ‘STEPS IN THE QUALITATIVE ANALYSIS OF A SALT.’ It outlines four steps in the analysis process: 1. Observation on the physical properties of the salt. 2. Effect of heat on the salt. 3. Test for anions and cations. 4. Confirmatory tests for cations and anions. Each step is represented by a numbered circle with a brief description next to it. The infographic is branded with the ‘Pandai’ logo.
 
Conformation Test for Anions
The image is an infographic titled ‘Anion test.’ It presents a flowchart for testing different anions: Carbonate ion, Chloride ion, Sulphate ion, and Nitrate ion. Each anion test is described as follows: - **Carbonate ion**: Tested with dilute HCl. The gas released turns limewater cloudy. - **Chloride ion**: Tested with dilute HNO₃ and AgNO₃. Forms white precipitate. - **Sulphate ion**: Tested with dilute HCl and BaCl₂. Forms white precipitate. - **Nitrate ion**: Tested with dilute H₂SO₄ and FeSO₄, followed by conc. H₂SO₄.
 
Confirmatory Test for Cations
  • Salt must be dissolved in water first before the confirmatory test.
  • The colour of the aqueous solution is observed.
Reactions between Cations and Sodium Hydroxide Solution, NaOH

This image is a flowchart categorizing the colors of cations in aqueous solutions. It is divided into two main categories: ‘Colourless’ and ‘Coloured.’ - Under ‘Colourless,’ the cations listed are NH4+, Mg2+, Ca2+, Zn2+, Al3+, and Pb2+. - Under ‘Coloured,’ there are three subcategories: - Blue: Cu2+ - Green: Fe2+ - Brown: Fe3+ The background of the flowchart is light blue, and the boxes are in various shades of red, blue, green, and brown.
Reactions between Cations and Sodium Hydroxide Solution, NaOH

This is a flowchart describing the reactions of aqueous cation solutions with sodium hydroxide (NaOH). - The chart starts with a central box labeled ‘Reaction of aqueous cation solution with sodium hydroxide, NaOH’ - It splits into two branches: ‘Colourless’ and ‘Coloured’. **Colourless branch:** - NH₄⁺: Ammonia gas is released when the mixture is heated. - Mg²⁺, Ca²⁺: White insoluble precipitate in excess NaOH. - Zn²⁺, Al³⁺, Pb²⁺: White soluble precipitate in excess NaOH. **Coloured branch:** - Cu²⁺: Blue insoluble precipitate in excess NaOH
Reaction between Cations and Ammonia Solution, NH3

This image is a flowchart showing the reactions of an aqueous solution with ammonia (NH3). It is divided into two main branches: colourless and coloured. - **Colourless branch**: - NH4+, Ca2+: No reaction. - Mg2+, Al3+, Pb2+: White insoluble precipitate in excess NH3. - Zn2+: White soluble precipitate in excess NH3. - **Coloured branch**: - Cu2+: Blue soluble precipitate in excess NH3. - Fe2+: Green insoluble precipitate in excess NH3. - Fe3+: Brown insoluble precipitate in excess NH3.
 
Confirmatory Test for Cation
This is a flowchart illustrating a cation test. It starts with the ‘Cation test’ at the top, branching into four sections for different cations: NH4+, Fe2+, Fe3+, and Pb2+. 1. **NH4+**: Add Nessler reagent. Result: Brown precipitate is formed. 2. **Fe2+**: Add acidified potassium manganate (VII) KMnO4 solution. Result: Purple color of the solution is decolorized. 3. **Fe3+**: Add potassium thiocyanate, KSCN solution. Result: Red solution is formed. 4. **Pb2+**: Add potassium iodide, KI and heat it up. Result.
 
Qualitative Analysis on Unknown Salts
The image is a flowchart with a light blue background, detailing the process of testing an unknown salt. It starts with observing the color, then moves to adding distilled water. If the salt is soluble, it proceeds to test for cations and anions in the aqueous solution. If not soluble, dilute nitric acid is added. Additional steps include heating and testing for gas.
 

 

 

 

 

The views expressed in the notes here are those of the contributor and don’t necessarily represent the views of pandai.

Qualitative Analysis

 
6.11 Qualitative Analysis
 
Qualitative Analysis of a Salt 
A technique used to identify the cation and anion present in a salt by analysing its physical and chemical properties.
 
The image is an infographic titled ‘STEPS IN THE QUALITATIVE ANALYSIS OF A SALT.’ It outlines four steps in the analysis process: 1. Observation on the physical properties of the salt. 2. Effect of heat on the salt. 3. Test for anions and cations. 4. Confirmatory tests for cations and anions. Each step is represented by a numbered circle with a brief description next to it. The infographic is branded with the ‘Pandai’ logo.
 
Conformation Test for Anions
The image is an infographic titled ‘Anion test.’ It presents a flowchart for testing different anions: Carbonate ion, Chloride ion, Sulphate ion, and Nitrate ion. Each anion test is described as follows: - **Carbonate ion**: Tested with dilute HCl. The gas released turns limewater cloudy. - **Chloride ion**: Tested with dilute HNO₃ and AgNO₃. Forms white precipitate. - **Sulphate ion**: Tested with dilute HCl and BaCl₂. Forms white precipitate. - **Nitrate ion**: Tested with dilute H₂SO₄ and FeSO₄, followed by conc. H₂SO₄.
 
Confirmatory Test for Cations
  • Salt must be dissolved in water first before the confirmatory test.
  • The colour of the aqueous solution is observed.
Reactions between Cations and Sodium Hydroxide Solution, NaOH

This image is a flowchart categorizing the colors of cations in aqueous solutions. It is divided into two main categories: ‘Colourless’ and ‘Coloured.’ - Under ‘Colourless,’ the cations listed are NH4+, Mg2+, Ca2+, Zn2+, Al3+, and Pb2+. - Under ‘Coloured,’ there are three subcategories: - Blue: Cu2+ - Green: Fe2+ - Brown: Fe3+ The background of the flowchart is light blue, and the boxes are in various shades of red, blue, green, and brown.
Reactions between Cations and Sodium Hydroxide Solution, NaOH

This is a flowchart describing the reactions of aqueous cation solutions with sodium hydroxide (NaOH). - The chart starts with a central box labeled ‘Reaction of aqueous cation solution with sodium hydroxide, NaOH’ - It splits into two branches: ‘Colourless’ and ‘Coloured’. **Colourless branch:** - NH₄⁺: Ammonia gas is released when the mixture is heated. - Mg²⁺, Ca²⁺: White insoluble precipitate in excess NaOH. - Zn²⁺, Al³⁺, Pb²⁺: White soluble precipitate in excess NaOH. **Coloured branch:** - Cu²⁺: Blue insoluble precipitate in excess NaOH
Reaction between Cations and Ammonia Solution, NH3

This image is a flowchart showing the reactions of an aqueous solution with ammonia (NH3). It is divided into two main branches: colourless and coloured. - **Colourless branch**: - NH4+, Ca2+: No reaction. - Mg2+, Al3+, Pb2+: White insoluble precipitate in excess NH3. - Zn2+: White soluble precipitate in excess NH3. - **Coloured branch**: - Cu2+: Blue soluble precipitate in excess NH3. - Fe2+: Green insoluble precipitate in excess NH3. - Fe3+: Brown insoluble precipitate in excess NH3.
 
Confirmatory Test for Cation
This is a flowchart illustrating a cation test. It starts with the ‘Cation test’ at the top, branching into four sections for different cations: NH4+, Fe2+, Fe3+, and Pb2+. 1. **NH4+**: Add Nessler reagent. Result: Brown precipitate is formed. 2. **Fe2+**: Add acidified potassium manganate (VII) KMnO4 solution. Result: Purple color of the solution is decolorized. 3. **Fe3+**: Add potassium thiocyanate, KSCN solution. Result: Red solution is formed. 4. **Pb2+**: Add potassium iodide, KI and heat it up. Result.
 
Qualitative Analysis on Unknown Salts
The image is a flowchart with a light blue background, detailing the process of testing an unknown salt. It starts with observing the color, then moves to adding distilled water. If the salt is soluble, it proceeds to test for cations and anions in the aqueous solution. If not soluble, dilute nitric acid is added. Additional steps include heating and testing for gas.
 

 

 

 

 

The views expressed in the notes here are those of the contributor and don’t necessarily represent the views of pandai.
Chapter : Acids, Bases and Salts
Topic : Describe the confirmatory tests to identify cations and anions
Form 4 Chemistry
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