Qualitative Analysis
Identification of Ions
There are 10 cations and 4 anions to be studied in our syllabus:
| Cation | |||
| Sodium | Na+ | Iron (II) | Fe2+ |
| Calcium | Ca2+ | Iron (III) | Fe3+ |
| Magnesium | Mg2+ | Lead(II) | Pb2+ |
| Aluminium | Al3+ | Copper (II) | Cu2+ |
| Zinc | Zn2+ | Ammonium | NH4+ |
| Anion | |
| Chloride ion | Cl– |
| sulphate ion | SO42- |
| nitrate ion | NO3– |
| carbonate ion | CO3– |
Steps in qualitative analysis
Identifying Gases
Oxygen (Glowing wooden splinter)
A glowing wooden splinter is inserted into the test tube that contain the gas.
The gas rekindles the glowing wooden splinter.
Hydrogen (Lighted Wooden Splinter)
A lighter wooden splinter is brought close to the mouth of the test tube that contain the gas.
A “pop” sound is produced.
Carbon dioxide (Lime Water)
The gas is directed to flow through lime water.
The lime water turn chalky.
Sulphur Dioxide (Potassium Dichromete(VI))
The gas is directed to flow through potassium dichromate(VI) solution.
The orange colour of potassium dichromate(VI) solution become green.
Chlorine (Moist Litmus Paper)
Moist blue litmus paper is inserted into the test tube that contain the gas.
The blue litmus paper turn red and then white.
Ammonia Gas (Moist litmus paper)
Moist red litmus paper is inserted into the test tube that contain the gas.
The red litmus paper turn blue.