Assertion (A) : Highest oxidation state of Mn is +7 in first series of transition elements.
Reason (R) : Transition metals exhibit variable oxidation states.
Show Hint
- Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- Assertion (A) is true, but Reason (R) is false.
- Assertion (A) is false, but Reason (R) is true.
The Correct Option is B
Solution and Explanation
Step 1: Examining the Assertion. Manganese has atomic number \[ 25 \] and electronic configuration \[ [Ar]\,3d^5\,4s^2. \] Thus, manganese possesses a total of seven valence electrons. Under suitable conditions, all these seven electrons can participate in bonding, allowing manganese to attain an oxidation state of \[ +7. \] Since no other element in the first transition series commonly exhibits an oxidation state higher than \(+7\), the Assertion is true.
Step 2: Examining the Reason. The Reason states that transition metals exhibit variable oxidation states. This statement is correct because transition elements can use both \(ns\) and \((n-1)d\) electrons in bonding. As a result, they commonly show multiple oxidation states. Therefore, the Reason is true.
Step 3: Checking whether the Reason explains the Assertion. The Assertion specifically refers to manganese having the highest oxidation state of \(+7\). The actual explanation is that manganese has the electronic configuration \[ 3d^5\,4s^2 \] which provides seven valence electrons available for bonding. The Reason merely states the general property that transition metals show variable oxidation states. It does not explain why manganese specifically reaches the oxidation state of \(+7\) or why it is the highest in the first transition series. Therefore, although the Reason is true, it is not the correct explanation of the Assertion.
Final Conclusion: Assertion (A) is true. Reason (R) is true. Reason (R) is not the correct explanation of Assertion (A). \[ \boxed{\text{Option (B)}} \]
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