- Introduction to Qualitative Analysis
Test for carbons using H2S, NaOH and NH4OH, Confirmatory Test for the cat ions.
Introduction to Qualitative Analysis
Qualitative analysis involves examination of colour, flame test, effect of heat and confirmatory test for cat ion and anions.
Cations are metallic ions e,g Ca2+, Pb2+, Al3+, Cu2+, Fe2+ , Fe3+, etc
Rules in Qualitative Analysis
- Your test solution should not be diluted too much
- Use only small quantity of reagents
Examination of colour and physical state of specimen
Substance colour physical state
1. Sulphur yellow solid
2. Copper(ii)oxide black solid
3. Iodine dark brown solid
4. Nitrogen iv oxide reddish brown gas
5. Mercury white liquid
- Deep green colour of flame indicate the presence of copper
- Deep yellow colour indicate the presence of sodium
- Brick red indicate calcium.
- State ten (10) examples of cations
- Give the colour of the following substance.
- Distilled water
- Iron filling
- Manganese(iv) oxide
- Benzoic acid.
Test for Cations
The Cations are Ca2+, Zn2+, Al3+, Pb2+, Fe2+. Fe3+, Cu2+, NH4 +
- Give the common reagents used for confirmatory test for cations.
- State the colour of the solution when the sample that contains the following dissolve in water:
a. Fe 2+ b. Cu 2+ c. Fe 3+
- The following give white gelatinous precipitate in NaOH except? (a) Al 3+ (b) pb2+ (c) CU 2+
- One of the following gives ‘pop’ sound when contact with lighted splint. (a) O2 (b) H2 (c ) NH3
- Example of cations that gives gas during its confirmatory test is (a) SO32- (b) SO42- (c) CO32-
- Deep green colour of flame indicate the presence of (a) sodium (b) calcium (c) copper (d) iron
- The only alkaline gas that changes moist red litmus paper to blue is (a)NH3 (b) HCl (c) NaOH (d) NH4OH
- Explain the confirmatory test for the following cations
- State the flame test for the following :
a. Calcium b. Copper c. sodium d. iron
School Chemstry by O.Y Ababio pages 165 – 183
Practical chemistry by R. I. Makanjuola pages 31-36.
Practical Chemistry for Schools and Colleges by Godwin O. Ojokuku pages 30 – 98.