Metal Carbonyls (G & E)
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The complex, [η4-C4H4)2M2(CO)3] obeys 18 electron rule and there is a triple bond between the metal atoms. Identify M from first row transition series
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Cr
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Fe
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Co
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Ni
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The test is for 15 marks and duration of the test is 20 minutes
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- 2.
V(CO)6 readily reacts with Na to give Na[V(CO)6] because V(CO)6 is an 18-electron complex
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True
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False
Correct Answer
A. FalseExplanation
The given statement is false. V(CO)6 does not readily react with Na to give Na[V(CO)6]. V(CO)6 is not an 18-electron complex.Rate this question:
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- 3.
[η5-CpM(CO)3]2 obeys 18 electron rule and has one M-M bond. M could be
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Mn(I), Cr(0)
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Cr(0), Fe(I)
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Ti(-I), Fe
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Ti (0), Fe
Correct Answer
A. Mn(I), Cr(0)Explanation
The complex [η5-CpM(CO)3]2 has a total of 18 valence electrons, which satisfies the 18 electron rule. Additionally, it has one M-M bond, indicating that the metal M is present in two oxidation states. The only combination of metal oxidation states that satisfies both of these conditions is Mn(I) and Cr(0). Therefore, Mn(I) and Cr(0) are the possible options for M in this complex.Rate this question:
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- 4.
The decreasing order of backbonding is
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[Ti(CO)6]2-< [V(CO)6]- < [Cr(CO)6] < [Mn(CO)6]+ < [Ir(CO)6]3+
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[V(CO)6]- < [Ti(CO)6]2-< [Cr(CO)6] < [Ir(CO)6]3+ < [Mn(CO)6]+
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[Ir(CO)6]3+ < [Mn(CO)6]+ < [Cr(CO)6] < [V(CO)6]- < [Ti(CO)6]2-
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[V(CO)6]- < [Ti(CO)6]2-< [Cr(CO)6] < [Mn(CO)6]+< [Ir(CO)6]3+
Correct Answer
A. [Ir(CO)6]3+ < [Mn(CO)6]+ < [Cr(CO)6] < [V(CO)6]- < [Ti(CO)6]2-Explanation
The correct answer is [Ir(CO)6]3+ < [Mn(CO)6]+ < [Cr(CO)6] < [V(CO)6]- < [Ti(CO)6]2-. This is because backbonding strength decreases as the oxidation state of the metal center increases. In this case, [Ir(CO)6]3+ has the highest oxidation state and therefore the weakest backbonding, while [Ti(CO)6]2- has the lowest oxidation state and the strongest backbonding.Rate this question:
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- 5.
In the linear complex, (CO) – M – (CO) group, one of the CO group is replaced by Et3N. Choose the correct statement that is related to the above substitution reaction
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υCO increases because Et3N is a pi-acid ligand
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υCO decreases because Et3N is a pi-acid ligand
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υCO increases because Et3N is not a pi-acid ligand
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υCO decreases because Et3N is not a pi-acid ligand
Correct Answer
A. υCO decreases because Et3N is not a pi-acid ligandExplanation
The correct statement is that υCO decreases because Et3N is not a pi-acid ligand. This is because Et3N is a Lewis base and not a pi-acid ligand. In the given linear complex, the CO ligands are pi-acceptor ligands, meaning they accept electron density from the metal center. When one of the CO ligands is replaced by Et3N, which is not a pi-acid ligand, it does not have the ability to accept electron density from the metal center like the CO ligands do. Therefore, the overall electron density around the metal center decreases, leading to a decrease in υCO.Rate this question:
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- 6.
[η5-Cp2Fe2(CO)3] is an 18 electron compound and shows single band at 1785 cm-1. Choose the statement from the following which describes its correct structure
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There are no bridging CO groups and the complex contains Fe-Fe double bond
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There are no terminal CO groups and the complex contains Fe-Fe double bond
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There are 2 terminal and 1 bridging CO groups and the complex contains Fe-Fe double bond
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There are 1 terminal and 2 bridging CO groups and the complex contains Fe-Fe double bond
Correct Answer
A. There are no terminal CO groups and the complex contains Fe-Fe double bondExplanation
The presence of a single band at 1785 cm-1 indicates the absence of terminal CO groups. Additionally, the complex contains an Fe-Fe double bond.Rate this question:
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Current Version
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Mar 18, 2023Quiz Edited by
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Jul 16, 2020Quiz Created by
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