1.

Splitting energy (Delta_(0)) can usually be measured form the absorption spectra of the complex ions. In simple cases when light is absorbed by a complex ion, an electron in one of the lower energy orbitals is excited to one of the higher energy orbital. The energy corresponding to the frequency of absorbed light is equal to Delta_(0). If value of Delta_(0) for the complex is in visible region, the complex is coloured and the value of Delta_(0) lies in ultraviolet or infrared region, the complex is colourless. For octahedral complexes, the cyrstal field stabilisation energy is given by CFSE= +[-0.4t_(2g)N+0.6e_(g)N_(1)]Delta_(0) Where N and N_(1) are number of electrons in t_(2g)" and "e_(g) orbitals respectively. The value of CFSE can be used for the correction of the experimental values of heats of hydration of divalent can be obtained by substracting the calculated CFSE values form the experimental values. Which of the following statements is correct ?

Answer»

ZINC (II) ION has a zero CFSE for any geometry.
A solution of `[Ti(H_(2)O)_(6)]^(3+)` is purple as the value of `Delta` for the `H_(2)O` complex is in the visible region.
Solution of `[Fe(CN)_(6)]^(4-)" and "[Fe(H_(2)O)_(6)]^(2+)` appear colourless in dilute solutions.
All of these

Solution :`Cr^(2+) impliesd^(4),t_(2g)^(1,1,1)eg^(1,0)`
CFSE`=-1.2 Delta_(0)+0.6Delta_(0)=-0.6 Delta_(0)`
NOTE :`349.75 cm^(-1)=1 KCAL//"mol"`
`implies CFSE=-0.6xx(13900)/(349.75)"kcal"//"mol"`
`=-23.84 kcal//mol~=-24`
Heat of hydration withoutCFSE will be :
`-450+24=-426 "kcal"//"ml"`


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