Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): in water is more stable than .

Reason (R): Enthalpy of hydration for is muc

Question

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A):  in water is more stable than .

Reason (R): Enthalpy of hydration for  is much less than that of .

In the light of the above statements, choose the correct answer from the options given below:

Canvas Classes · Accepted Answer

Assertion (A):  is more stable than  in water — TRUE ✓

disproportionates in water:

is thermodynamically more stable in aqueous solution.

Reason (R): Hydration enthalpy of  is much LESS than  — FALSE ✗

This is the opposite of the truth. The hydration enthalpy of  is much GREATER than  due to:
- Higher charge (+2 vs +1)
- Smaller ionic radius (higher charge density)

It is this large hydration enthalpy of  that makes it more stable in water — compensating for the higher ionisation energy.

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