Question

Assertion (A): Highest oxidation state of Mn is +7 in most of the transition elements.
Reason (R): Transition metals exhibit variable oxidation states.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

Mn shows maximum +7 oxidation state, but not all transition metals do. Variable oxidation state is a general property of transition elements.

Answer 1

The Correct Option is D

To determine the correctness of the given assertion and reason regarding the highest oxidation states in transition metals, let's analyze each statement:

1. Assertion (A): Highest oxidation state of Mn is +7 in most of the transition elements.
   • The assertion suggests that the highest oxidation state observed for manganese (Mn), which is +7, is common across most transition metals.
   • However, this is not accurate. While Mn does indeed have a highest oxidation state of +7, it is not true for most transition metals.
   • For example, chromium (Cr) can also achieve a +6 oxidation state as seen in CrO₄²⁻, and iron (Fe) has a highest known oxidation state of +3 or +6 in certain compounds like Fe₂O₃ and K₂FeO₄ respectively.
   • Additionally, some transition metals like iron (Fe) and copper (Cu) do not reach such high oxidation states; copper, for example, commonly exhibits +1 and +2 oxidation states.
   • Therefore, the assertion (A) is false.
2. Reason (R): Transition metals exhibit variable oxidation states.
   • This statement is true because transition metals typically exhibit variable oxidation states. This property arises due to the involvement of their d-electrons in bonding.
   • This characteristic allows transition metals to form various compounds by adapting different oxidation states.

Given this analysis:

• Assertion (A) is false as it incorrectly generalizes the oxidation state +7 for most transition metals, which is not correct.
• Reason (R) is true as transition metals do indeed exhibit variable oxidation states.

Thus, the correct answer is: Assertion (A) is false, but Reason (R) is true.