Question 4 - MCQs from NCERT Exemplar - Chapter 2 Class 10 - Acids, Bases and Salts (Term 1)

Which of the following salts does not contain water of crystallisation?

(A) Blue vitriol

(B) Baking soda

(C) Washing soda

(D) Gypsum

Answer

Water of crystallisation is the amount of water molecules present in a unit of salt

From the given options, let’s check out their formula

• Blue vitriol i.e. CuSO ₄ .5H ₂ O has 5 water of crystallization
• Baking soda i.e. NaHCO ₃ has no water of crystallisation
• Washing soda i.e. Na ₂ CO ₃ .10H ₂ O has 10 water of crystallization
• Gypsum i.e. CaSO ₄ .2H ₂ O has 2 water of crystallisation

Among the following options, only baking soda does not contain water of crystallisation

So, the correct option is (b) Baking soda