ExamsMy practice
Ques. 1JEE Main 2024, 9 April (Morning Shift)
The electronic configuration of Cu(II) is 3d9 whereas that of Cu(I) is 3d10. Which of the following is correct?
- Cu(II) is more stable
- Cu(II) is less stable
- Cu(I) and Cu(II) are equally stable
- Stability of Cu(I) and Cu(II) depends on nature of copper salts
Answer
(1) Cu(II) is more stable
Solution
In aqueous solution Cu+ disproportionates: 2Cu+(aq) Cu2+(aq) + Cu(s).
This is because the hydration enthalpy of the small, highly charged Cu2+ is much more negative than that of Cu+ and more than compensates for the second ionisation enthalpy of Cu.
Hence Cu(II) is more stable than Cu(I), in spite of the 3d10 configuration of Cu+.
Answer: (1)