The point at which the chlorine demand of water is fully met is called?

KPSC Staff Nurse - 2018

Community Health Nursing

Easy

Appeared in: KPSC Staff Nurse - 2018

Explanation

The 'Break point' is the precise moment in the water chlorination process where the demand for chlorine by impurities (like ammonia, iron, and organic matter) has been completely satisfied.
Before this point, added chlorine is consumed by these impurities and is not available for disinfection.
After the breakpoint is reached, any further chlorine added becomes 'free residual chlorine', which is the active form that kills bacteria and viruses.
Achieving breakpoint is crucial to ensure not only initial disinfection but also to provide a protective residual that keeps water safe throughout the distribution system.

Option A: This is a general, non-technical term. Disinfection is the overall process of killing microorganisms, not a specific point related to chlorine demand.
Option C: This term is from physical chemistry and refers to the point at which a solvent can no longer dissolve a solute. It does not describe the chemical reactions involved in chlorination.
Option D: This is not a standard or recognized term in water treatment. It may be intended to cause confusion with 'free residual chlorine', which is the substance that appears after the breakpoint.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Breakpoint Chlorination in Water Purification as background academic context rather than a clinical decision trigger.
Understanding water purification methods like breakpoint chlorination is fundamental for community health nurses to prevent waterborne diseases such as cholera, typhoid, dysentery, and hepatitis A.
Nurses play a key role in educating communities about the importance of safe drinking water and simple purification methods like boiling or using chlorine tablets correctly.
What if? If water is highly turbid (cloudy), the chlorine demand will be very high. Simply adding a standard amount of chlorine may not be enough to reach the breakpoint, leaving the water unsafe. In such cases, pre-treatment like sedimentation and filtration is necessary before chlorination.

How to Approach the Question

Identify the core concept of the question, which is about the terminology used in water chlorination.
Recognize the key phrase 'chlorine demand is fully met'. This points to a specific event in the chemical process.
Recall the stages of chlorination: chlorine is first used up by impurities (demand), then it forms combined chlorine, and finally, it exists as free residual chlorine.
The transition point between satisfying the demand and the appearance of free residual chlorine is known as the 'breakpoint'.
Evaluate the options based on this technical definition. 'Break point' is the precise term.
Eliminate other options: 'Disinfection point' is too general, 'Saturation point' is from a different scientific context, and 'Free point' is not a standard term.

Concept Tested & Keywords

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