Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion A : Beryllium has less negative value of reduction potential compared to the other alkaline earth metals.
Reason R : Beryllium has large hydration energy due to small size of Be$^{2+}$ but relatively large value of atomization enthalpy
In the light of the above statements, choose the most appropriate answer from the options given below :
Solution
The most appropriate answer is Both A and R are correct and R is the correct explanation of A.
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<b>Assertion A</b> 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 Be<sup>2+</sup> to Be metal.
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<b>Reason R</b> 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 Be<sup>2+</sup> ions. The strong Be-Be bonds make it difficult to reduce Be<sup>2+</sup> to Be metal, and the small size of Be<sup>2+</sup> ions leads to a large hydration energy. This makes it energetically unfavorable to remove the Be<sup>2+</sup> ion from the aqueous phase and reduce it to Be metal, which results in a less negative value of reduction potential for beryllium.
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Therefore, both Assertion A and Reason R are correct, and Reason R provides the correct explanation for Assertion A.
About this question
Subject: Chemistry · Chapter: s-Block Elements · Topic: Alkali Metals
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