Which of the following is the main disadvantage associated with hard water in domestic and industrial use?
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AGreater soap consumption and poor lathering
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BScaling of boilers and heat exchangers
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CCorrosion and incrustation of pipes and fittings
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DAdverse effects on cooking quality and taste of food
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EAll of the above
Answer
Correct Answer: All of the above
Explanation
Introduction / Context:Hard water contains elevated concentrations of calcium and magnesium ions. While not a direct health hazard, hardness creates multiple operational and domestic problems that increase costs and reduce equipment life and performance.
Given Data / Assumptions:
- Hardness primarily due to Ca²⁺ and Mg²⁺ salts.
- Applications include bathing, laundry, cooking, and industrial heating systems.
Concept / Approach:Hardness interferes with soap (forming scum), precipitates scale in heated systems, and can promote corrosion-incrustation cycles. These issues collectively degrade efficiency, increase energy use, and impact user experience.
Step-by-Step Solution:
Soap consumption rises because Ca²⁺/Mg²⁺ form insoluble salts with fatty acids.Scaling in boilers reduces heat transfer, causing higher fuel consumption and risk of overheating.In pipes, deposits reduce cross-sectional area and may accelerate localized corrosion.Cooking in hard water can toughen certain foods and affect taste and texture.Verification / Alternative check:Industrial water treatment programs (softening/conditioning) are standard precisely to prevent these problems, confirming their practical significance.
Why Other Options Are Wrong:Each of options a–d individually states valid disadvantages; since all are true, the most complete choice is the combination, i.e., option e.
Common Pitfalls:Confusing temporary and permanent hardness; assuming hardness is only a “soap” problem while ignoring energy penalties from scale.
Final Answer:All of the above