Which of the following statements is correct with respect to the metal carbonyls of I^(st) transition series?

Which of the following statements is correct with respect to the metal

1.	Which of the following statements is correct with respect to the metal carbonyls of I^(st) transition series?
Answer» As `M-Cpi` BONDING increase, the `C-O` bond length increases. As positive CHARGE on the central metal atom increases, the `C-O` bond length increases. As electron density on the central metal atom increases, the `C-O` bond length increases. (1) and (3) both Solution :order of `C-O` bond STRENGTH: `[Mn(CO)_(6)]^(+)gt[Cr(CO)_(6)]gt[V(CO)_(6)]^(-)gt[Ti(CO)_(6)]^(2-)` and `[Ni(CO)_(4)]gt[Co(CO)_(4)]gt[Fe(CO)_(4)]^(2-)` (1). True statement (2). `As+` ve charge on te central metal atom increases, the less readily the metal can donate electron density into the `PI^(*)` orbitals of CO ligand to weaken the `C-O` bond. (3). In the corbonylate anions, the metal has a greater electron density to be dispersed, with the result that `M-Cpi` bonding is enhanced and the `C-O` bond is diminished in strength.