The transition metal in which of the following compound has zero oxidation state.

Step-by-step solution

Oxidation states of given transition metals are as follows array |c|c|c| S.No. & Compound & Oxidation state of metal [t] 4 * 1. & ~K ₂ Cr ₂ O ₇ & array l 2(+1)+2(x)+7(-2)=0 x=+6 array & & i.e. Cr =+6 & & Here, oxidation state of K =1 & & Oxidation state of O =-2 [t] 3 * 2. & KMnO ₄ & 1+x+(-8)=0 & & x=+7 i.e. M n=+7 & & Here, oxidation state of K =1 [t] 2 * 3. & CrO ₅ & x+5(-2)=0 & & x=+10 i.e. Cr =+10 [t] 3 * 4. & Fe ( CO )₅ & x+5(0)=0 & & x=0 i.e. Fe =0 & & array l Here, CO is a neutral ligand thus Fe is having ox