Which of the following is used in disinfection of water?

RUHS, Jaipur, PB B.Sc Nursing Entrance-2023

Community Health Nursing

Easy

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2023

Explanation

Bleaching powder, also known as chlorinated lime (CaOCl2), is a standard chemical agent used for the disinfection of water.
According to Park's Textbook of Preventive & Social Medicine, chlorine compounds have long been used for water treatment due to their potent bactericidal and virucidal properties.
When added to water, bleaching powder releases hypochlorous acid (free chlorine), which is a powerful germicide that effectively kills most pathogens.
This method is cost-effective and is widely practiced in India for disinfecting community water supplies, wells, and for emergency water purification.

Option A: Cetrimide is a quaternary ammonium compound used as an antiseptic for cleaning skin and wounds. It acts as a detergent and is not used for purifying drinking water.
Option B: Formaldehyde is a highly toxic gas used in its aqueous solution (formalin) for fumigation of rooms and sterilization of heat-sensitive instruments. It is not safe for human consumption.
Option D: Hexachlorophene is a phenolic antiseptic incorporated into soaps for skin disinfection, particularly against gram-positive bacteria. Its use is restricted due to the risk of neurotoxicity, and it is never used for water purification.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Chemical methods of water disinfection as background academic context rather than a clinical decision trigger.
Nurses in community health settings play a vital role in educating the public about safe water practices, including methods for disinfecting water at home, especially during floods or outbreaks of waterborne diseases like cholera and typhoid.
In disaster management, ensuring a safe water supply is a primary nursing responsibility to prevent epidemics. Knowledge of emergency disinfection methods using bleaching powder is essential.
What if? If the question asked for a physical method of water disinfection for a household, the answer would be boiling. Boiling water vigorously for at least one minute kills all pathogenic organisms.

How to Approach the Question

First, identify the key concept in the question, which is the 'disinfection of water'. This specifically refers to making water safe to drink.
Evaluate each option based on its primary application in healthcare and public health.
Recall or deduce the difference between an antiseptic (for living tissue), a sterilant (for instruments/surfaces), and a water disinfectant.
Eliminate options known for other uses: Cetrimide and Hexachlorophene are skin antiseptics. Formaldehyde is a toxic sterilant/fumigant.
Identify Bleaching powder as the common chemical agent used for large-scale water chlorination, a standard public health measure.
Confirm your choice by selecting the agent specifically indicated for making water potable.

Concept Tested & Keywords

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