What causes the blue colour of copper sulphate crystals?
Answer and explanation
Correct answer: Water of crystallisation
Copper sulphate crystals are hydrated copper sulphate, CuSO₄·5H₂O, and contain a definite number of water molecules within their crystal structure. At this school level, the characteristic blue appearance is associated with the hydrated crystalline form and its water of crystallisation. Therefore option A is the expected answer. Sodium ions, chlorine gas, and hydrogen gas are not constituents responsible for these crystals’ blue colour.
Frequently asked questions
What is the correct answer to this question?
Water of crystallisation
Why is this the correct answer?
Copper sulphate crystals are hydrated copper sulphate, CuSO₄·5H₂O, and contain a definite number of water molecules within their crystal structure. At this school level, the characteristic blue appearance is associated with the hydrated crystalline form and its water of crystallisation. Therefore option A is the expected answer. Sodium ions, chlorine gas, and hydrogen gas are not constituents responsible for these crystals’ blue colour.
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.
