## Core Concept
Bleaching powder, chemically known as calcium hypochlorite (Ca(ClO)_2_), is a strong disinfectant and a widely used agent for water treatment. Its effectiveness as a bleaching agent is primarily due to its ability to release chlorine. Understanding its properties and uses is crucial in various medical and environmental applications.

## Why the Correct Answer is Right
The correct answer, which is not provided in the query, typically relates to the properties or uses of bleaching powder that are not accurate. Generally, bleaching powder is used for disinfection, water treatment, and as a bleaching agent. It acts by releasing hypochlorous acid (HOCl), which is the active form of chlorine responsible for its disinfectant properties.

## Why Each Wrong Option is Incorrect
- **Option A:** Without specific details on what Option A states, we can infer that any statement claiming bleaching powder is used for disinfection, acts as a strong oxidizing agent, or is effective against a wide range of pathogens would be true.
- **Option B:** Similarly, if Option B mentions a correct application or property of bleaching powder, such as its use in swimming pools for water disinfection or its role in the production of chloroform, it would be incorrect to say it's not true.
- **Option C:** If Option C suggests that bleaching powder decomposes on storage to release chlorine gas, this is a true statement and highlights one of its limitations.
- **Option D:** If Option D provides a false statement about bleaching powder, such as it being ineffective against spores or certain viruses at certain concentrations, this would be the correct choice if it accurately represents something not true about bleaching powder.

## Clinical Pearl / High-Yield Fact
A key point to remember is that bleaching powder's effectiveness can be influenced by pH; it is most effective at a slightly acidic to neutral pH range because this favors the formation of HOCl. Additionally, its use in healthcare settings requires careful handling due to its corrosive nature and potential to release toxic fumes.

## Correct Answer: D.