Correct option is B
The correct answer is (b) Statement-II is true, and Statement-I is false.
Explanation:
Statement-I is incorrect. Anhydrous sodium carbonate (Na₂CO₃) is not used in soda-acid fire extinguishers. Soda-acid fire extinguishers typically use sodium bicarbonate (NaHCO₃) or baking soda as the primary component because it releases carbon dioxide (CO₂) when it reacts with an acid, helping to extinguish flames. Sodium carbonate, on the other hand, does not produce CO₂ in the same manner when exposed to acid, so it is not effective for this purpose.
Statement-II is correct. Anhydrous sodium carbonate can be dissolved in water and recrystallized to form washing soda crystals (Na₂CO₃·10H₂O), which contain 10 molecules of water of crystallization. This transformation from anhydrous to hydrated sodium carbonate is commonly used in applications like laundry detergents due to its water-softening properties.
Important Key Points:
- Anhydrous sodium carbonate is commonly known as soda ash.
- Washing soda (Na₂CO₃·10H₂O) is the decahydrate form of sodium carbonate.
- Washing soda is used to soften hard water by precipitating out calcium and magnesium ions.
- Soda-acid fire extinguishers utilize sodium bicarbonate and an acid to generate CO₂ for fire suppression.
- Sodium carbonate and sodium bicarbonate, while related, serve distinct functions due to their chemical properties.
- Sodium bicarbonate is chosen in fire extinguishers due to its ability to release CO₂ upon acid reaction.
Information Booster:
- Sodium carbonate (Na₂CO₃): Also known as soda ash, it is commonly used in glassmaking, detergents, and as a water softener.
- Sodium bicarbonate (NaHCO₃): Known as baking soda, it’s used in cooking, as an antacid, and in fire extinguishers for its CO₂ release upon reaction.
- Washing soda (Na₂CO₃·10H₂O): Created by recrystallizing sodium carbonate, it’s used in cleaning products and water treatment to remove hardness.
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