Bleaching Powder (Preparation) MCQs Quiz | Class 10
This quiz covers Class X Science (Code 086), Unit I: Chemical Substances – Nature and Behaviour. It specifically focuses on the topic of Bleaching Powder, detailing its preparation method, reactants, and products. Test your understanding of how Calcium Oxychloride is formed, then submit to check your score and download the PDF answer sheet.
Overview: Preparation of Bleaching Powder
Bleaching powder is chemically known as Calcium Oxychloride. Its chemical formula is represented as CaOCl2, although the actual composition is quite complex. It is produced by the action of chlorine gas on dry slaked lime.
The Chemical Reaction
The preparation involves the reaction between Calcium Hydroxide (dry slaked lime) and Chlorine gas. The chlorine used in this process is typically the by-product of the Chlor-alkali process (electrolysis of brine).
Equation:
Ca(OH)2 + Cl2 yields CaOCl2 + H2O
Key Components
- Reactant 1: Dry Slaked Lime (Calcium Hydroxide, Ca(OH)2). It must be dry for the reaction to be effective.
- Reactant 2: Chlorine Gas (Cl2). Acts as the oxidizing agent in other contexts but here reacts to form the salt.
- Product: Bleaching Powder (CaOCl2).
- By-product: Water (H2O).
Quick Summary Table
| Substance | Chemical Formula | Role in Preparation |
|---|---|---|
| Slaked Lime | Ca(OH)2 | Main Reactant (Base) |
| Chlorine | Cl2 | Reactant (Gas) |
| Bleaching Powder | CaOCl2 | Main Product |
Important Notes
- Bleaching powder smells strongly of chlorine because it slowly releases chlorine gas when exposed to air (reaction with CO2).
- It is soluble in water, but a small residue of unreacted lime often remains, making the solution look milky.
Extra Practice Questions
- What is the common name for Calcium Oxychloride? (Answer: Bleaching Powder)
- Which gas is released when bleaching powder reacts with dilute acids? (Answer: Chlorine)
- Why is dry slaked lime used instead of lime water? (Answer: To produce solid bleaching powder efficiently)
- What is the source of chlorine used in this preparation? (Answer: Chlor-alkali process)
- Is bleaching powder an oxidizing agent or reducing agent? (Answer: Oxidizing agent)
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