What is the formula of washing soda?
Answer and explanation
Correct answer: Na₂CO₃·10H₂O
Washing soda is the common name for hydrated sodium carbonate. The sodium carbonate part is Na₂CO₃, and the crystal contains ten molecules of water of crystallisation, so its complete formula is Na₂CO₃·10H₂O. Sodium bicarbonate, NaHCO₃, is baking soda. CaSO₄·½H₂O is plaster of Paris, whereas CaSO₄·2H₂O is gypsum. Hence option A is unambiguously correct.
Frequently asked questions
What is the correct answer to this question?
Na₂CO₃·10H₂O
Why is this the correct answer?
Washing soda is the common name for hydrated sodium carbonate. The sodium carbonate part is Na₂CO₃, and the crystal contains ten molecules of water of crystallisation, so its complete formula is Na₂CO₃·10H₂O. Sodium bicarbonate, NaHCO₃, is baking soda. CaSO₄·½H₂O is plaster of Paris, whereas CaSO₄·2H₂O is gypsum. Hence option A is unambiguously correct.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
