Membrane filter technique is used for testing
- AMicrobiological contaminationCorrect
- BHeavy metals
- CHardness
- DTurbidity
Solution
Concept
The membrane filter technique counts coliform bacteria in water.
Step-by-step solution
1. Filter a known volume of water through a membrane with 0.45 μm pores. 2. Bacteria stay on the membrane. 3. Place the membrane on a nutrient medium and incubate. 4. Count the colonies. This is a microbiological test, so the answer is (A).
Explanation
In the membrane filter technique, water passes through a fine membrane that traps bacteria. The membrane is then incubated, and the coliform colonies are counted. It is a quick and direct test for bacterial contamination.
Why the other options are wrong
B: Heavy metals are tested by AAS or ICP. C: Hardness is tested by EDTA titration. D: Turbidity is tested by a turbidimeter or nephelometer.
Shortcut
Membrane filter equals bacteria (coliform) count.
Common mistake
Thinking 'filter' means a turbidity test.
Correct answer: A) Microbiological contamination