Which of the following is an example of Chemical disinfectant?

NCL (MP) Nursing Officer - 2020

Applied Microbiology & Infection control

Easy

Appeared in: NCL (MP) Nursing Officer - 2020

Explanation

Bleaching powder, also known as chlorinated lime (calcium hypochlorite), is a chemical agent used for disinfection.
It falls under the category of halogen disinfectants.
Its antimicrobial action is due to the release of free chlorine, which is a strong oxidizing agent that destroys microorganisms.
It is commonly used for disinfecting water, surfaces, and excreta like faeces and urine.

Option A: Burning (incineration) is a physical method of sterilization, not chemical disinfection. It uses high temperatures to destroy all organic matter, including microorganisms.
Option B: Boiling is a physical method of disinfection that uses moist heat. While effective against many bacteria and viruses, it does not reliably kill bacterial spores and is therefore not a method of sterilization.
Option D: An autoclave is a device that uses a physical method—steam under pressure—to achieve sterilization. It is not a chemical disinfectant.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of Disinfection and Sterilization Methods as background academic context rather than a clinical decision trigger.
In a hospital, selecting the correct decontamination method is critical for infection control. Using a chemical disinfectant like bleach is appropriate for environmental surfaces, while an autoclave is necessary for surgical instruments to prevent surgical site infections.
Nurses must understand the difference between disinfection and sterilization to ensure patient safety. For example, an instrument used for an invasive procedure must be sterilized, not just disinfected.
What if the item to be decontaminated was a heat-sensitive endoscope? None of the physical methods like autoclaving or boiling would be appropriate. A high-level chemical disinfectant (or chemical sterilant) like glutaraldehyde or peracetic acid would be the correct choice.

How to Approach the Question

First, identify the key term in the question: 'Chemical disinfectant'. This requires you to differentiate between chemical and physical methods of microbial control.
Analyze each option to determine its category.
Option A, Burning: Recall that this involves fire/incineration, which is a physical process of applying extreme heat.
Option B, Boiling: This uses hot water, a form of moist heat, which is a physical method.
Option C, Bleaching Powder: Recognize this as a specific chemical compound used for cleaning and disinfecting.
Option D, Autoclave: Remember that this is a machine that uses steam under pressure, another physical (heat-based) method.

Concept Tested & Keywords

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E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart A (pp 26-201 of 604) pp. 127-129, 128-130