Fading of blue colour of copper sulphate solution is linked with decrease of which ion?
Answer and explanation
Correct answer: Copper(II) ion
The blue colour of aqueous copper sulphate is mainly due to hydrated copper(II) ions, \(\mathrm{Cu^{2+}}\). When these ions are converted into copper metal during a reaction, their concentration in the solution decreases and the blue colour fades. Iron(II) ions may form and change the solution’s appearance, but the direct reason for loss of blue colour is the decrease in \(\mathrm{Cu^{2+}}\) ions. Exam tip: Link the colour of a solution with the metal ion responsible for it.
Frequently asked questions
What is the correct answer to this question?
Copper(II) ion
Why is this the correct answer?
The blue colour of aqueous copper sulphate is mainly due to hydrated copper(II) ions, \(\mathrm{Cu^{2+}}\). When these ions are converted into copper metal during a reaction, their concentration in the solution decreases and the blue colour fades. Iron(II) ions may form and change the solution’s appearance, but the direct reason for loss of blue colour is the decrease in \(\mathrm{Cu^{2+}}\) ions. Exam tip: Link the colour of a solution with the metal ion responsible for it.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
