Question

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 :

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. (A) is correct but (R) is not correct
• C. Both (A) and (R) are correct but (R) is not the correct explanation of $( A )$
• D. (A) is not correct but (R) is correct

Answer 1

Answer: (A)

Both (A) and (R) are correct and (R) is the correct explanation of (A)

Answer 2

2Cu+→Cu2++Cu
The stability of Cu2+(aq) rather than Cu+(aq), is due to the much more negative Δhyd ​H of Cu2+ (aq) than Cu+(aq), which more than compensates for the second ionisation enthalpy of Cu.