JEE Main 2023 — S Block Elements Question with Solution

The most appropriate answer is Both A and R are correct and R is the correct explanation of A.

Assertion A states that beryllium has a less negative value of reduction potential compared to the other alkaline earth metals. This assertion is correct, as beryllium has higher ionization energy and a smaller atomic radius than the other alkaline earth metals, which makes it more difficult to reduce Be²⁺ to Be metal.

Reason R provides an explanation for Assertion A. Beryllium has a relatively large value of atomization enthalpy due to the strong Be-Be bonds in the solid state, but it also has a large hydration energy due to the small size of Be²⁺ ions. The strong Be-Be bonds make it difficult to reduce Be²⁺ to Be metal, and the small size of Be²⁺ ions leads to a large hydration energy. This makes it energetically unfavorable to remove the Be²⁺ ion from the aqueous phase and reduce it to Be metal, which results in a less negative value of reduction potential for beryllium.

Therefore, both Assertion A and Reason R are correct, and Reason R provides the correct explanation for Assertion A.