Stretching vibration of NO + is at ____ than that for NO itself : | TestHub

Passage / Comprehension

There are many known monosubstitution products of the $[F e (CN)_{6}]^{4 -}$ ion, the most important being the red salt sodium nitrosopentacyanoferrate(II), $N a_{2} [F e (CN)_{5} NO] \cdot 2 H_{2} O$ , commonly called sodium nitroprusside.

This results from the action of nitric acid or sodium nitrite on the hexacyano complex:

$[F e (CN)_{6}]^{4 -} + 4 H^{+} + N O_{3}^{-} \to [F e (CN)_{5} NO]^{2 -} + C O_{2} + N H_{4}^{+}$

$[F e (CN)_{6}]^{4 -} + N O_{2}^{-} + H_{2} O \to [F e (CN)_{5} NO]^{2 -} + C N^{-} + 2 O H^{-}$

The anion of this compound, which is diamagnetic, contains coordinated NO with an interatomic distance of $1.13 \overset{˚}{A}$ and a stretching vibration at $1947 c m^{- 1}$ . With sulfide ion, it gives the purple anion $[F e (CN)_{5} NOS]^{4 -}$ , a reaction which forms the basis of a sensitive test for sulfide.

Stretching vibration of $NO^{+}$ is at $____$ than that for NO itself :

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Answer:

Solution:

The stretching vibration frequency of NO⁺ is higher than that of the neutral NO molecule.

Explanation:

Bond Order: According to Molecular Orbital Theory, the bond order of NO is 2.5, while for NO⁺ it is 3.0 (due to the removal of an electron from an antibonding orbital).

Bond Strength: A higher bond order indicates a stronger and shorter bond.

Vibrational Frequency: Since the force constant ( $k$ ) is directly proportional to bond strength, the stretching frequency ( $ν$ ) increases as the bond order increases ( $ν \propto k$ ).

Values: In sodium nitroprusside, NO⁺ vibrates at approximately $1947 c m^{- 1}$ , whereas neutral NO vibrates at around $1876 c m^{- 1}$ .

Chemistry - Coordination Chemistry Question with Solution | TestHub

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