0.5% chlorine solution is prepared by using?

Hariyana-CHO-2021

Applied Microbiology & Infection control (E5)

Easy

Appeared in: Hariyana-CHO-2021

Explanation

The question asks which type of bleaching powder is used to prepare a 0.5% chlorine solution.
The percentages in the options (10%, 20%, 30%, 40%) refer to the concentration of 'available chlorine' in the bleaching powder.
Bleaching powder with an available chlorine content of 30-35% is a standard and commonly available grade for disinfection.
Therefore, 30% bleaching powder is the most suitable answer, representing a typical product used for this purpose.
Using the standard formula, approximately 16.7 grams of 30% bleaching powder would be mixed with one liter of water to achieve a 0.5% chlorine concentration.

Option B: While 10% bleaching powder can be used, it is a lower concentration, requiring a much larger quantity (50g per liter) to achieve the desired 0.5% solution, making it less efficient.
Option C: Using 20% bleaching powder would require 25g per liter. It is a viable option but less common than the 30-35% standard grade.
Option D: 40% bleaching powder is a higher concentration and less common than the standard 30-35% grade. It would require 12.5g per liter.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Preparation of chlorine disinfection solution using bleaching powder as background academic context rather than a clinical decision trigger.
A 0.5% chlorine solution (5000 ppm) is a high-level disinfectant used for decontaminating surfaces contaminated with blood, body fluids, or other potentially infectious materials (e.g., in spills, HIV, or Hepatitis B care settings).
A weaker 0.1% solution (1000 ppm) is typically used for general surface disinfection and sanitizing water for drinking.
What if? If you needed to disinfect a surface with a large spill of blood, using a 0.1% solution would be insufficient. You must use the stronger 0.5% solution to ensure proper decontamination and prevent the transmission of bloodborne pathogens.

How to Approach the Question

First, identify that the question is about preparing a chemical solution, which involves a specific formula or standard.
Recognize that 'bleaching powder' quality is measured by its '% available chlorine'. The options likely refer to this property.
Recall or deduce that there is a standard range for available chlorine in bleaching powder used for disinfection. This range is typically 30-35%.
Evaluate the options based on this standard. '30% Bleaching powder' fits within this common range.
Confirm your understanding by applying the formula: Amount (g) = (Required % / Available %) x 1000. This shows how any concentration could be used, but the question asks what is 'used,' implying a standard.
Select the option that represents the most common or standard material used for the task.

Concept Tested & Keywords

Concept Tested: Preparation of chlorine disinfection solution using bleaching powder.
Stem keywords: 0.5% chlorine solution, prepared, bleaching powder
Lead-in keywords: BEST, MOST RELEVANT CLUE

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E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart B (pp 233-449 of 464) pp. 33-35, 34-36