During chlorination of water, the point at which the chlorine demand is met is called

Appeared in: UPPSC 2017

Explanation

Break point chlorination refers to the precise moment in the water treatment process when the demand for chlorine by various impurities (like ammonia and organic matter) has been completely satisfied.
Once the break point is reached, any further addition of chlorine results in a proportional increase in 'free residual chlorine'.
This free residual chlorine (FRC) is the active form that disinfects the water and provides a protective barrier against subsequent contamination during storage and distribution.
Achieving the break point is crucial for ensuring that the water is not only disinfected but also remains safe for consumption.

Option B: Super chlorination is a method, not a point in a process. It involves adding a much larger dose of chlorine than is needed to meet the chlorine demand.
Option C: Contact period refers to the duration of time, not a point of chemical saturation. It is the time required for the disinfectant to act on microorganisms.
Option D: Chlorine demand is the amount of chlorine that gets used up by impurities in the water; it is not the point at which this process is complete.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Water Disinfection and Chlorination Process as background academic context rather than a clinical decision trigger.
Understanding water purification is fundamental for community health nurses to prevent waterborne diseases like cholera, typhoid, and hepatitis A.
Nurses can educate communities on safe water practices and the importance of adequate chlorination, especially in rural areas or during emergencies.
What if the water source has a high level of ammonia? The chlorine demand would be significantly higher, meaning more chlorine must be added to reach the break point. This also increases the risk of forming disinfection byproducts, which must be monitored.

How to Approach the Question

First, identify the core of the question. It asks for the specific term for a 'point' where 'chlorine demand is met'.
Analyze the keywords: 'point', 'chlorine demand', 'met'. This indicates a specific milestone in a chemical process.
Evaluate each option against this requirement.
Option A, 'Break point chlorination', specifically defines a point or stage in the process.
Option B, 'Super chlorination', describes a method of adding excess chlorine.
Option C, 'Contact period', refers to a duration of time.

Concept Tested & Keywords

QC65Zo7eAgNOxkfm-E0kwI

E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart B (pp 233-449 of 464) p. 32-34

Practise the full UPPSC 2017

Attempt every question from this paper in a timed mock, then review the full solution for each one.