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🧪 Chemistry  ·  Chemistry in Everyday Life  ·  NEET & JEE

Phenol is used as both an antiseptic and a disinfectant. What determines which role it plays?

Answer: Concentration: a dilute solution (~0.2%) acts as an antiseptic on living tissue, while a more concentrated solution (~1%) acts as a disinfectant on inanimate objects.

  • A Its underlying molecular structure is said to physically rearrange itself largely between these two quite distinct chemical uses under most conditions encountered
  • B Concentration: a dilute solution (~0.2%) acts as an antiseptic on living tissue, while a more concentrated solution (~1%) acts as a disinfectant on inanimate objects
  • C It is claimed to function mainly ever as a mild antiseptic, with disinfectant-grade phenol actually being a wholly different molecule as frequently observed in practice
  • D The particular ambient temperature at which the phenol solution happens to be applied is what is said to determine its specific role in many documented cases according to conventional understanding

Correct answer: B. Concentration: a dilute solution (~0.2%) acts as an antiseptic on living tissue, while a more concentrated solution (~1%) acts as a disinfectant on inanimate objects

Explanation: The same chemical, phenol, is classified as an antiseptic or a disinfectant purely based on concentration and the surface it is applied to - dilute on living tissue (antiseptic), more concentrated on inanimate objects (disinfectant) where it would otherwise damage living cells.

Micelle Formation: How Soap Removes Greasegrease / oilhydrophobic tail (in oil) - hydrophilic head (in water, blue circles)

The hydrophobic hydrocarbon tail of each soap/detergent molecule dissolves into an oily dirt droplet, while the hydrophilic (ionic) head stays in the surrounding water - trapping the grease inside a micelle that rinses away with water.

Concept context

Drugs and how they interact with biological targets, chemicals in food, and cleansing agents (soaps and detergents) - chemistry applied directly to daily life and healthcare.

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