To determine the correct answer, we need to understand the properties and uses of each compound.
Na₂CO₃ · 10H₂O:
- Na₂CO₃ · 10H₂O is a chemical formula for sodium carbonate decahydrate.
- It is commonly known as "washing soda" or "soda ash."
- The compound is a white crystalline substance that contains water molecules in its structure.
- It is highly soluble in water and has a strong alkaline nature.
- Washing soda is mainly used in laundry detergents, water treatment, and as a cleaning agent.
Baking Soda:
- Baking soda, also known as sodium bicarbonate (NaHCO₃), is a different compound from Na₂CO₃ · 10H₂O.
- Baking soda is a white crystalline powder that is also soluble in water.
- It is commonly used in baking as a leavening agent to help dough rise.
- Baking soda also has various other household uses, such as cleaning, deodorizing, and as an antacid.
Bleaching Powder:
- Bleaching powder, or calcium hypochlorite (Ca(ClO)₂), is a completely different compound from Na₂CO₃ · 10H₂O.
- It is a white powder with a strong chlorine odor.
- Bleaching powder is commonly used as a disinfectant, for bleaching purposes, and as a water treatment agent.
Tartaric Acid:
- Tartaric acid, or C₄H₆O₆, is yet another different compound from Na₂CO₃ · 10H₂O.
- It is a crystalline organic acid that is commonly found in fruits like grapes.
- Tartaric acid is used in the food and beverage industry as an acidulant, flavor enhancer, and stabilizer.
Based on the above information, we can conclude that the correct answer is A: washing soda, as Na₂CO₃ · 10H₂O is the chemical formula for washing soda.