Here’s a explanation of the main methods used in qualitative analysis without any equations:
1. Precipitation Test
- Some substances form a solid (precipitate) when they react with certain chemicals.
- This solid helps identify what is present in the sample.
- Example: Some salts form a white solid when tested with specific solutions.
2. Flame Test
- Certain metals give distinct colors when their compounds are heated in a flame.
- Example: Sodium gives a yellow flame, potassium gives a lilac flame.
3. Color Reactions
- Some substances change color when they react with specific chemicals.
- The color change helps identify the substance.
- Example: Iron gives a red color with some chemicals.
4. Complex Formation
- Some substances form colored or distinct compounds when they combine with special reagents.
- Example: Copper turns deep blue with certain solutions.
5. Odor or Gas Test
- Some substances release a specific smell or gas when treated.
- Example: Ammonium compounds release ammonia gas, which has a sharp smell.
6. Solubility Test
- Some substances dissolve in water or other liquids, while others do not.
- Solubility can help identify them.
- Example: Some salts form solids that don’t dissolve easily in water.
7. Spectroscopic Methods
- Advanced tools can detect substances based on their light absorption or molecular structure.
- Example: Instruments can identify organic compounds in a mixture.
In short: qualitative analysis is about finding out what is present using color, solid formation, flame, smell, or special instruments.