Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R) Assertion (A): $Cu ^{2+}$ in water is more stable than $Cu ^{+}$ Reason (R): Enthalpy of hydration for $Cu ^{2+}$ is much less than that of $Cu ^{+}$ In the light of the above statements, choose the correct answer from the options given below :
Both (A) and (R) are correct and (R) is the correct explanation of (A)
(A) is correct but (R) is not correct
Both (A) and (R) are correct but (R) is not the correct explanation of $( A )$
(A) is not correct but (R) is correct
Show Solution
The Correct Option isA
Solution and Explanation
The question involves understanding the stability of different oxidation states of copper ions in water and linking this understanding to the enthalpy of hydration. Let's dissect the assertion and the reason given in the question:
Assertion (A):\(Cu^{2+}\) in water is more stable than \(Cu^{+}\).
Copper typically exists in two common oxidation states: \(+1 (Cu^+)\) and \(+2 (Cu^{2+})\).
The stability of an ion in aqueous solution is influenced by factors such as enthalpy of hydration and loss of electrons.
\(Cu^{2+}\) being a more common and stable oxidation state is due to its favorable hydration enthalpy and the energetics of its electron configuration.
Reason (R): Enthalpy of hydration for \(Cu^{2+}\) is much less than that of \(Cu^+\).
Hydration enthalpy is the energy released when ions are solvated by water molecules.
A more negative enthalpy of hydration means the ion is more stabilized by interaction with water molecules.
For \(Cu^{2+}\), this enthalpy is significantly negative, making it more stable in water compared to \(Cu^+\) whose hydration enthalpy is less negative.
Based on the above understanding, let's evaluate the given options:
Both (A) and (R) are correct and (R) is the correct explanation of (A): This option is accurate; the reason explains why \(Cu^{2+}\) is more stable due to its hydration enthalpy.
(A) is correct but (R) is not correct: This is incorrect because the reason provided is accurate and relevant.
Both (A) and (R) are correct but (R) is not the correct explanation of (A): This is not accurate as the reason does indeed explain the stability difference.
(A) is not correct but (R) is correct: This is incorrect because the assertion itself is true.
Therefore, the correct answer is: Both (A) and (R) are correct and (R) is the correct explanation of (A).
