Temporary hardness of water is removed by?

Appeared in: BHU NO - 2015

Explanation

Boiling is the correct method for removing temporary hardness from water.
This process works by converting soluble calcium and magnesium bicarbonates into insoluble carbonates through heating.
These insoluble carbonates precipitate out of the water, which can then be separated, effectively reducing the hardness.

Option B: Filtration removes suspended solids and turbidity from water but does not remove dissolved minerals like calcium and magnesium bicarbonates that cause temporary hardness.
Option C: The SODIS (Solar Water Disinfection) method uses UV radiation from the sun to kill harmful microorganisms. It is a method of disinfection, not water softening, and has no effect on mineral content.
Option D: Adding chlorine to water is a chemical disinfection process used to kill bacteria, viruses, and other pathogens. It does not remove the dissolved minerals that are responsible for water hardness.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Water Hardness and Purification Methods as background academic context rather than a clinical decision trigger.
In community health nursing, advising families on safe and appropriate water treatment methods is a key role. Understanding the difference between softening and disinfection is crucial for providing correct health education.
Hard water can lead to scale buildup in household appliances like kettles and water heaters, and also in medical equipment like autoclaves and humidifiers, potentially causing damage and inefficiency. Knowing how to manage it is important.
What if the question asked about removing permanent hardness? The answer would involve chemical methods like ion-exchange (water softeners) or adding washing soda (sodium carbonate), as boiling is ineffective against sulfates and chlorides.

How to Approach the Question

First, identify the key concept in the question, which is 'temporary hardness' of water.
Recall the definition of temporary hardness: it is caused by dissolved bicarbonates of calcium and magnesium.
Differentiate this from permanent hardness, which is caused by sulfates and chlorides.
Evaluate each option based on its primary mechanism of action.
Boiling applies heat, which is known to decompose bicarbonate salts.
Filtration, SODIS, and chlorination are methods for removing particles or killing microbes, not for altering dissolved mineral content.

Concept Tested & Keywords

QX283ATnHV109AlGgV153c

E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart B (pp 233-449 of 464) pp. 44-46, 33-35

Practise the full BHU NO - 2015

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