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NEETChemistryd and f Block Elements

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Copper(I) ion is unstable in aqueous solution and undergoes disproportionation to Copper(II) ion and solid copper. Reason (R): Copper(II) ion has a more stable 3d^9 electronic configuration compared to the completely filled 3d¹⁰ configuration of Copper(I) ion. In the light of the above statements,

Options

  1. AAssertion (A) is true but Reason (R) is false.
  2. BBoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
  3. CBoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
  4. DAssertion (A) is false but Reason (R) is true.

Correct answer

A. Assertion (A) is true but Reason (R) is false.

Step-by-step solution

Assertion (A) is true. In aqueous solutions, Cu^+ undergoes disproportionation: 2Cu^+_ (aq) Cu²⁺_ (aq) + Cu_ (s) . Reason (R) is false. The Cu^+ ion has a completely filled 3d¹⁰ configuration, which is electronically more stable than the 3d^9 configuration of Cu²⁺ . The instability of Cu^+ in aqueous solution is not due to its electronic configuration, but rather because the high negative hydration enthalpy of the Cu²⁺ ion more than compensates for the second ionization enthalpy of copper. Answer: Assertion (A) is

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