AIIMS 2018 Chemistry Reduction of Complexes MCQ Question

The complex V(CO)₆ can be reduced to the anionic form [V(CO)₆]⁻ by gaining an electron, which stabilizes the oxidation state of vanadium in a lower oxidation state. Option D is correct because it accurately represents the reduced form of the complex. Option A (V(CO)₆) is the neutral form and does not indicate reduction, while option B ([V(CO)₆]⁺) suggests a cationic form, which is not a reduction. Option C ([V(CO)₆]²⁻) implies a greater reduction than what is achieved, as the complex typically only accepts one electron to form a single negative charge.