Q31. The correct bond order for carbon-oxygen bond in following metal carbonyls [Cr(CO)6], [V(CO)6]-

Q: What is the correct answer for CUET UG Chemistry Q31?

The correct answer is A. In metal carbonyls, the C-O bond order is inversely related to the extent of synergic bonding (back-bonding). Back-bonding from metal d-orbitals to CO π* antibonding orbitals strengthens the M-C bond and weakens the C-O bond, thus decreasing the C-O bond order.More electron density on the central metal atom leads to more back-bonding and thus a weaker C-O bond (lower bond order).Less electron dens

Q: Q31. The correct bond order for carbon-oxygen bond in following metal carbonyls [Cr(CO)6], [V(CO)6]-, [Mn(CO)6]+ is (a) [V(CO)6]- < [Cr(CO)6] < [Mn(CO)6]+ (b) [V(CO)] = [Cr(CO)6] = [Mn(CO)6]+ (c)…

The correct answer is A. In metal carbonyls, the C-O bond order is inversely related to the extent of synergic bonding (back-bonding). Back-bonding from metal d-orbitals to CO π* antibonding orbitals strengthens the M-C bond and weakens the C-O bond, thus decreasing the C-O bond order.More electron density on the central metal atom leads to more back-bonding and thus a weaker C-O bond (lower bond order).Less electron dens

Q: What are the options for this CUET UG Chemistry question?

A. (a) [V(CO)6]- < [Cr(CO)6] < [Mn(CO)6]+ · B. (b) [V(CO)] = [Cr(CO)6] = [Mn(CO)6]+ · C. (c) [Mn(CO)6]+ < [Cr(CO)6] < [V(CO)6]- · D. (d) [Cr(CO)6] < [V(CO)6]- < [Mn(CO)6]+

Question

Q31. The correct bond order for carbon-oxygen bond in following metal carbonyls [Cr(CO)6], [V(CO)6]-, [Mn(CO)6]+ is
(a) [V(CO)6]- < [Cr(CO)6] < [Mn(CO)6]+
(b) [V(CO)] = [Cr(CO)6] = [Mn(CO)6]+
(c) [Mn(CO)6]+ < [Cr(CO)6] < [V(CO)6]-
(d) [Cr(CO)6] < [V(CO)6]- < [Mn(CO)6]+

FirstInTest · Accepted Answer

In metal carbonyls, the C-O bond order is inversely related to the extent of synergic bonding (back-bonding). Back-bonding from metal d-orbitals to CO π* antibonding orbitals strengthens the M-C bond and weakens the C-O bond, thus decreasing the C-O bond order.More electron density on the central metal atom leads to more back-bonding and thus a weaker C-O bond (lower bond order).Less electron density on the central metal atom leads to less back-bonding and thus a stronger C-O bond (higher bond order).The oxidation states of the central metal atoms are:[V(CO)6]-: V is in -1 oxidation state (most electron-rich)[Cr(CO)6]: Cr is in 0 oxidation state[Mn(CO)6]+: Mn is in +1 oxidation state (least electron-rich)Therefore, the order of increasing electron density on the metal is [Mn(CO)6]+ < [Cr(CO)6] < [V(CO)6]-.This means the order of increasing back-bonding is [Mn(CO)6]+ < [Cr(CO)6] < [V(CO)6]-.And the order of *increasing C-O bond order* (decreasing C-O bond strength) is:[V(CO)6]- < [Cr(CO)6] < [Mn(CO)6]+.

Answer

(a) [V(CO)6]- < [Cr(CO)6] < [Mn(CO)6]+

Answer

(b) [V(CO)] = [Cr(CO)6] = [Mn(CO)6]+

Answer

(c) [Mn(CO)6]+ < [Cr(CO)6] < [V(CO)6]-

Answer

(d) [Cr(CO)6] < [V(CO)6]- < [Mn(CO)6]+

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