In which substance is the presence of water of crystallisation easily shown by colour change?
Answer and explanation
Correct answer: Blue copper sulphate
The governing concept is water of crystallisation, which is chemically bound water present in certain salt crystals. Blue copper sulphate is hydrated copper sulphate, CuSO4·5H2O. On heating, it loses this water and changes from blue to white anhydrous copper sulphate; adding water restores the blue colour. The other options do not show this characteristic reversible colour change in this test.
Frequently asked questions
What is the correct answer to this question?
Blue copper sulphate
Why is this the correct answer?
The governing concept is water of crystallisation, which is chemically bound water present in certain salt crystals. Blue copper sulphate is hydrated copper sulphate, CuSO4·5H2O. On heating, it loses this water and changes from blue to white anhydrous copper sulphate; adding water restores the blue colour. The other options do not show this characteristic reversible colour change in this test.
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.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
