Previous Year Question
Washing soda is the common name of which of the following?
A.
Calcium Carbonate
B.
Potassium Carbonate
C.
Sodium Carbonate
D.
Magnesium Carbonate
Correct Answer: C
Detailed Solution
Among the given options, the correct answer is sodium carbonate. However, its precise chemical form should be understood.
Washing soda is actually sodium carbonate decahydrate, with the formula:
Na₂CO₃·10H₂O
According to NCERT, washing soda is obtained by recrystallisation of sodium carbonate and is represented as Na₂CO₃·10H₂O.
The 10H₂O represents ten molecules of water known as water of crystallisation. NCERT also lists its uses in the glass, soap and paper industries, as a domestic cleaning agent, and for removing permanent hardness of water.