Bonding in Metal Carbonyls

Q. In which compound synergic effect is present that relieves the metal of excess negative charge

1. $\left[Ni\right(CO{)}_4]$
2. $[NiC{l}_4{]}^{2-}$
3. $[CuC{l}_4{]}^{2-}$
4. $\left[Mn\right(H_{2}O{)}_6{]}^{2+}$

Q. Which of the following statement regarding bonding in metal carbonyls is correct?

1. Metal–carbon bond in metal carbonyls possesses​ only $\sigma$ character.
2. Metal–carbon bond in metal carbonyls possesses​ only $\pi$ character.
3. Metal–carbon $\sigma$ bond is formed by the donation of lone pair of ​ electrons of carbonyl carbon into vacant d-orbital of metal.
4. None of the above

Q. In $Fe(CO{)}_5$ the $Fe-C$ bond has:

1. Sigma character
2. $\pi$ character
3. Both $\sigma$ and $\pi$ character.
4. Cannot predict

Q. In $Fe(CO{)}_5$, the Fe - C bond possesses

1. $\pi$ character only
2. Both $\sigma$ and $\pi$ character
3. $\sigma$ character only
4. Cannot be predicted

Q.

Which of the following has longest C-O bond length? (Free C-O bond length in CO is 1.128 A.)

1. $\left[Co\right(CO{)}_4{]}^{-}$

2. $\left[Fe\right(CO{)}_4{]}^{2-}$

3. $\left[Mn\right(CO{)}_6{]}^{+}$

4. $Ni(CO{)}_4$

Q. Which of the following carbonyls will have the strongest $C-O$ bond?

1. $\left[Fe\right(CO{)}_5]$
2. $\left[Mn\right(CO{)}_6{]}^{+}$
   
3. $\left[Cr\right(CO{)}_6]$
4. $\left[V\right(CO{)}_6{]}^{-}$
   

Q. Among the following metal carbonyls, the $CO$ bond order is the lowest in:

1. $\left[Mn\right(CO{)}_6{]}^{+}$
2. $\left[Fe\right(CO{)}_5]$
3. $\left[Cr\right(CO{)}_6]$
4. $\left[V\right(CO{)}_6{]}^{-}$

Q. In which complex is the $C-O$ bond length maximum?

1. $V(CO{)}_6^{-}$
2. $Cr(CO{)}_6$
3. $Mn(CO{)}_6^{+}$
4. $Fe(CO{)}_6^{2+}$

Q.

What is the shape of $Fe(CO{)}_5$ molecule and which of the following d - orbitals involved in hybridization?

1. Tetrahedral $d_{x^2-y^2}$

2. Trigonal bipyramidal, $d_{x^2-y^2}$

3. Trigonal bipyramidal, $d_{z^2}$

4. Square pyramidal

Q. Among the following metal carbonyls, the C-O bond order is lowest in:

1. $\left[Mn\right(CO{)}_6{]}^{+}$
2. $\left[Fe\right(CO{)}_5]$
3. $\left[Cr\right(CO{)}_6]$
4. $\left[V\right(CO{)}_6{]}^{-}$

Q. The correct statement(s) regarding the binary transition metal carbonyl compounds is/are: (Atomic number: Fe = 26, Ni = 28)

1. Total number of valence shell electrons at metal centre in $Fe(CO{)}_5$ or $Ni(CO{)}_4$ is 16
2. These are predominantly low spin in nature
3. Metal-carbon bond strengthens when the oxidation state of the metal is lowered
4. The carbonyl C - O bond weakens when the oxidation state of the metal is increased