Introduction to CFT

Q.

Does aqua $\left(H_{2}O\right)$ come under strong field ligand or weak field ligand according To VBT Theory?

Q. According to the spectrochemical series, which is the strongest field ligand:

1. $C{N}^{-}$
2. $N{O}_2^{-}$
3. $N{H}_3$
4. $ethane1,2-diamine\left(en\right)$

Q. What is the hybridisation of oxygen in O2?

Q. What is meant by crystal field splitting energy ? On the basis of crystal field theory, write the electronic configuration of $d^4$ in terms of $t_{2g}$ and $e_g$ in an octahedral field when
(i) ${\Delta }_0>P$
(ii) ${\Delta }_0<P$

Q. Arrange the following in the increasing order of ligand field strength (according to spectrochemical series)

1. Br ^-
2. CN^-
3. H₂O
4. S^2-
5. NH₃

Q. Which one of the following ligand has the highest field strength?

1. $C{N}^{-}$
2. $N{O}_2^{-}$
3. Ethylenediamine
4. $N{H}_3$

Q.

What are the original colors of the ${\mathrm{FeSO}}_4$solution and of the ${\mathrm{FeCl}}_3$ solution?

Q. Low spin complex of $d^6-$ cation in an octahedral field will have the following crystal field stabilization energy
$({\Delta }_0=$ crystal field splitting energy in an octahedral field, $P=$ Electron pairing energy)

1. $\frac{-12}{5}{\Delta }_0+P$
2. $\frac{-12}{5}{\Delta }_0+3P$
3. $\frac{-2}{5}{\Delta }_0+2P$
4. $\frac{-2}{5}{\Delta }_0+P$

Q. Low spin tetrahedral complexes are not formed because :

1. for tetrahedral complexes, the CFSE is lower than pairing energy.
2. for tetrahedral complexes, the CFSE is higher than pairing energy.
3. electrons do not go to $e_g$ in case of tetrahedral complexes
4. tetrahedral compleces are formed by weak field ligands only.

Q. Which of the following is the correct order of increasing field strength of ligands to form coordination compounds ?

1. $F^{-}<SC{N}^{-}<C_2{O}_4^{2-}<C{N}^{-}$
2. $C{N}^{-}<C_2{O}_4^{2-}<SC{N}^{-}<F^{-}$
3. $SC{N}^{-}<F^{-}<C_2{O}_4^{2-}<C{N}^{-}$
4. $SC{N}^{-}<F^{-}<C{N}^{-}<C_2{O}_4^{2-}$

Q. Weakest ligand out of the following is

1. Depends upon the compound
2. $N{H}_3$
3. $C{N}^{-}$
4. $F^{-}$

Q.

What is the color of zinc metal?

Q. The CFSE for a high-spin d⁴ octahedral complex is

1. –0.6Δ_oct
2. –1.8Δ_oct
3. –1.6Δ_oct
4. –1.2Δ_oct

Q. Why the presence of 3d orbital in potassium increases its volume

Q. Arrange the following in order of decreasing number of unpaired electrons:
$\left(I\right)\left[Fe\right(H_{2}O{)}_6{]}^{2+}\left(II\right)\left[Fe\right(CN{)}_6{]}^{3-}$
$\left(III\right)\left[Fe\right(CN{)}_6{]}^{4-}\left(IV\right)\left[Fe\right(H_{2}O{)}_6{]}^{3+}$

1. $\left(IV\right),\left(I\right),\left(II\right),\left(III\right)$
2. $\left(I\right),\left(II\right),\left(III\right),\left(IV\right)$
3. $\left(III\right),\left(II\right),\left(I\right),\left(IV\right)$
4. $\left(II\right),\left(III\right),\left(I\right),\left(IV\right)$

Q. What is crystal field splitting energy? Draw a figure to show spitting of degenerate orbitals in an octahedral crystal field?

Q. The number of oxygen atom in borax which do not form $p\pi -p\pi$ backbonding are:

Q. Among the following complexes (K-P), $K_3\left[Fe\right(CN{)}_6\left]\right(K),$ $\left[Co\right(N{H}_3{)}_6\left]C{l}_3\right(L),N{a}_3[Co(oxalate{)}_3{]}^{-3},[Ni\left(H_{2}O{)}_6\right]C{l}_2\left(N\right),$
$K_2\left[Pt\right(CN{)}_4\left]\right(O\left)\text{and}\right[Zn\left(H_{2}O{)}_6\right]\left(N{O}_3{)}_2\right(P),$ the diamagnetic complexes are

1. L, M, N, O
2. K, L, M, N
3. K, M, O, P
4. L, M, O, P

Q. The spectrum produced by white light is Options: Emission spectrum Continuous spectrum Absorption spectrum Both emission and continuous spectrum

Q.

The ion of chlorine is?

Q. Explain the violet colour of $\left[Ti\right(H_{2}O{)}_6{]}^{3+}$ complex on basis of the crystal field theory?

Q. $d$ – orbitals of metal lose their degeneracy in:

1. Blue vitriol
2. Anhydrous $CuS{O}_4$
3. Potassium ferrocyanide
4. Potassium ferricyanide

Q. The number of geometrical isomers of $\left[Co\right(N{H}_3{)}_3\left(N{O}_3{)}_3\right]$ :

1. $0$
2. $2$
3. $3$
4. $4$

Q.

The following ion shows colour not due to d-d transistion.

1. $C{r}_{2}O{{}_7}^{2-}$
2. $MnO{{}_4}^{-}$
3. $CrO{{}_4}^{2-}$
4. All

Q. Assertion :According to crystal field theory, during complex formation, the d - orbitals split and form two sets of orbitals $t_{2g}$ and $e_g$ Reason: Splitting of d - orbitals occurs only in case of strong field ligand

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. The CFSE for a high-spin d⁴ octahedral complex is

1. –0.6Δ_oct
2. –1.8Δ_oct
3. –1.6Δ_oct
4. –1.2Δ_oct

Q. Why is [Ni(CN)4]2- dsp2 and [Ni(CO)4] sp3 even though CO is stronger ligand than CN-?

Q. How do 'd' orbitals split in an octahedral crystal field?

Q. Number of bridging $CO$ ligands in $\left[M{n}_2{\left(CO\right)}_{10}\right]$ is _____.

Q. Explain hybridisation of so2. By molecular orbital theory.