CFSE in Octahedral and Tetrahedral Complexes

Q. Number of unpaired electrons present in $\left[Mn\right(CN{)}_6{]}^{3–}$ is:

1. Zero
2. 2
3. 4
4. 3

Q.

Which of these statements about $\left[Co\right(CN{)}_6{]}^{3-}$ is true?

1. $\left[Co\right(CN{)}_6{]}^{3-}$ has four unpaired electrons and will be in a low-spin configuration.
   

2. $\left[Co\right(CN{)}_6{]}^{3-}$ has four unpaired electrons and will be in a high-spin configuration.
   

3. $\left[Co\right(CN{)}_6{]}^{3-}$ has no unpaired electrons and will be in a high-spin configuration.

4. $\left[Co\right(CN{)}_6{]}^{3-}$ has no unpaired electrons and will be in a low-spin configuration.

Q.

Why is ${\left[{\mathrm{PtCl}}_4\right]}^{2-}$ square planar?

Q.

For a high spin metal ion in the octahedral and tetrahedral fields, the values of the crystal field stabilisation energies are

1. $-2.4{∆}_0\mathrm{and}-0.6{∆}_{\mathrm{t}}$

2. $–1.6{∆}_0\mathrm{and}–0.4{\mathrm{\Delta }}_{\mathrm{t}}$

3. $–0.4{∆}_0\mathrm{and}–0.27{∆}_{\mathrm{t}}$

4. $–0.4{∆}_0\mathrm{and}–0.6{∆}_{\mathrm{t}}$

Q. Low spin complex of $d^6-$ cation in an octahedral field will have the following energy:
$({\Delta }_0=$ crystal feild splitting energy in an octahedral feild, 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. chromium crytallizes in bcc lattice whose density is 7.2 g/cm^3 the edge length is 288.4 pm find avogadro number

Q.

Consider that a $d^6$ metal ion $\left(M^{2+}\right)$ forms a complex with aqua ligands, and the spin only magnetic moment of the complex is $4.9$$\mathrm{BM}$. The geometry and the crystal field stabilization energy of the complex is:

1. Tetrahedral and $-0.6{∆}_t$

2. Tetrahedral and $-1.6{∆}_t+1P$

3. Octahedral and $-1.6{∆}_0$

4. Octahedral and $-2.4{∆}_0+2P$

Q.

The species that has a spin only magnetic moment of $5.9\mathrm{BM}$ is

1. $[\mathrm{Ni}{\left(\mathrm{CN}\right)}_4{]}^{-2}(\mathrm{square}\mathrm{planar})$

2. $\mathrm{Ni}{\left(\mathrm{CO}\right)}_4\left(\mathrm{Td}\right)$

3. ${\left[{\mathrm{MnBr}}_4\right]}^{-2}\left(\mathrm{Td}\right)$

4. ${\left[{\mathrm{NiCl}}_4\right]}^{-2}\left(\mathrm{Td}\right)$

Q.

The colour of the coordination compounds depends on the crystal field splitting. What will be the correct order of absorption of wavelength of light in the visible region, for the complexes, $\left[Co\right(N{H}_3{)}_6{]}^{3+},\left[Co\right(CN{)}_6{]}^{3-},\left[Co\right(H_{2}O{)}_6{]}^{3+}$
$\left[Co\right(N{H}_3{)}_6{]}^{3+},\left[Co\right(CN{)}_6{]}^{3-},\left[Co\right(H_{2}O{)}_6{]}^{3+}$
(a) $\left[Co\right(CN{)}_6{]}^{3-}>\left[Co\right(N{H}_3{)}_6{]}^{3+}>\left[Co\right(H_{2}O{)}_6{]}^{3+}$
(b) $\left[Co\right(N{H}_3{)}_6{]}^{3+}>\left[Co\right(H_{2}O{)}_6{]}^{3+}>\left[Co\right(N{H}_3{)}_6{]}^{3+}$
(c) $\left[Co\right(H_{2}O{)}_6{]}^{3+}>\left[Co\right(N{H}_3{)}_6{]}^{3+}>\left[Co\right(CN{)}_6{]}^{3-}$
(d) $\left[Co\right(CN{)}_6{]}^{3-}>\left[Co\right(N{H}_3{)}_6{]}^{3+}>\left[Co\right(H_{2}O{)}_6{]}^{3+}$

Q. The crystal field splitting energy for octahedral and tetrahedral complexes is related as

1. ${\Delta }_t$ ≈ $\frac{4}{9}$${\Delta }_o$
2. ${\Delta }_o$≈ $\frac{4}{9}$${\Delta }_t$
3. ${\Delta }_t$ ≈ $\frac{1}{2}$${\Delta }_o$
4. ${\Delta }_o$ ≈ 2${\Delta }_t$

Q.

Which of the following complex is/are low spin complex(es)?

1. $\left[Co\right(N{H}_3{)}_6{]}^{3+}$

2. $[Co{F}_6{]}^{3-}$

3. $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$

4. $\left[Fe\right(CN{)}_6{]}^{4-}$

Q.

What is crystal field splitting energy? How does the magnitude of ${\Delta }_0$ decide the actual configuration of d-orbitals in a coordination entity?

Q. The pair(s) of complexes wherein both exhibit tetrahedral geometry is(are)
(Note: py = pyridine
Given: Atomic numbers of Fe, Co, Ni and Cu are 26, 27, 28 and 29, respectively)

1. $\left[FeC{l}_4{]}^{-}\text{and}\right[Fe(CO{)}_4{]}^{2-}$
2. $\left[Co\right(CO{)}_4{]}^{-}\text{and}[CoC{l}_4{]}^{2-}$
3. $\left[Ni\right(CO{)}_4{]}^{-}\text{and}\left[Ni\right(CN{)}_4{]}^{2-}$
4. $\left[Cu\right(py{)}_4{]}^{+}\text{and}\left[Cu\right(CN{)}_4{]}^{3-}$

Q. Consider the following metal complexes:
$\left[Co\right(N{H}_3{)}_6{]}^{3+}$
$\left[CoCl\right(N{H}_3{)}_5{]}^{2+}$
$\left[Co\right(CN{)}_6{]}^{3–}$
$\left[Co\right(N{H}_3{)}_5\left(H_{2}O\right){]}^{3+}$
The spin-only magnetic moment value of the
complex that absorbs light with shortest wavelength
is B.M. (Nearest integer)

Q.

Among the following pairs of complexes, in which case is the ${\Delta }_0$ value is higher for the first one?

1. $\left[Co\right(N{H}_3{)}_6{]}^{3+}and\left[Co\right(CN{)}_6{]}^{3-}$

2. $\left[Co\right(H_2{O}_6{]}^{2+}and\left[Co\right(H_{2}O{)}_6{]}^{3+}$

3. $\left[Co\right(H_2{O}_6{]}^{3+}>\left[Rh\right(H_{2}O{)}_6{]}^{3+}$

4. $\left[Rh\right(H_{2}O{)}_6{]}^{3+}and\left[Co\right(H_2{O}_6{]}^{3+}$

Q.

Why are low spin tetrahedral complexes not formed?

Q. Which of the following order of energies of molucular orbitals of $N_2$ is correct?

1. $\left(\pi 2p_y\right)<\left(\sigma 2p_z\right)>\left({\pi }^{\ast }2p_x\right)\approx \left({\pi }^{\ast }2p_y\right)$
2. $\left(\pi 2p_y\right)>\left(\sigma 2p_z\right)>\left({\pi }^{\ast }2p_x\right)\approx \left({\pi }^{\ast }2p_y\right)$
3. $\left(\pi 2p_y\right)<\left(\sigma 2p_z\right)>\left({\pi }^{\ast }2p_x\right)\approx \left({\pi }^{\ast }2p_y\right)$
4. $\left(\pi 2p_y\right)<\left(\sigma 2p_z\right)<\left({\pi }^{\ast }2p_x\right)\approx \left({\pi }^{\ast }2p_y\right)$

Q. The number of molecule(s) or ion(s) from the following having non-planar structure is _____.

$N{O}_3^{-},H_2{O}_2,B{F}_3,PC{l}_3,Xe{F}_4,S{F}_4,Xe{O}_3,P{H}_4^{+},S{O}_3,\left[Al\right(OH{)}_4{]}^{-}$

Q.

The CFSE for octahedral $[CoC{l}_6{]}^{4-}$ is 18000 $c{m}^{-1}$. The CFSE for tetrahedral $[CoC{l}_4{]}^{2-}$ will be

Q. Match List-I with List-II.

$\begin{array}{cccc}& \text{List-I}& & \text{List-II}\\ & \text{(Compound)}& & \text{(Shape)}\\ \text{(A)}& {\text{BrF}}_5& \text{(I)}& \text{bent}\\ \text{(B)}& {\left[\text{CrF}{}_6\right]}^{3-}& \text{(II)}& \text{square pyramidal}\\ \text{(C)}& {\text{O}}_3& \text{(III)}& \text{trigonal bipyramidal}\\ \text{(D)}& {\text{PCl}}_5& \text{(IV)}& \text{octahedral}\end{array}$

Choose the correct answer from the options given below :

1. $\text{(A)-(I), (B)-(II), (C)-(III), (D)-(IV)}$
2. $\text{(A)-(III), (B)-(IV), (C)-(II), (D)-(I)}$
3. $\text{(A)-(II), (B)-(IV), (C)-(I), (D)-(III)}$
4. $\text{(A)-(IV), (B)-(III), (C)-(II), (D)-(I)}$

Q.

Jahn-Teller effect is not observed in high spin complexes of

1. $d^8$

2. $d^4$

3. $d^7$

4. $d^9$

Q. Geometrical shapes of the complexes formed by the reaction of $N{i}^{2+}$ with $C{l}^{–},C{N}^{–}$ and $H_{2}O$, respectively are

1. Square planar, tetrahedral and octahedral
2. Octahedral, square planar and octahedral
3. Octahedral, tetrahedral and square planar
4. Tetrahedral, square planar and octahedral

Q.

How many nodal surface $\left(\mathrm{s}\right)$ can $5\mathrm{s}$ orbital can have?

Q. The elements of 3d transition series are given as:

$\begin{array}{cccccccccc}Sc& Ti& V& Cr& Mn& Fe& Co& Ni& Cu& Zn\end{array}$

Answer the following:
(i) Write the element which is not regarded as a transition element. Give reason.
(ii) Which element has the highest m.p.?
(iii) Write the element which can show an oxidation state of +1.
(iv) Which element is a strong oxidizing agent in +3 oxidation state and why?

Q. (a) Account for the following:
(i) Transition metals show variable oxidation states.
(ii) Zn, Cd and Hg are soft metals.
(iii) $E^o$ value for the $M{n}^{3+}/M{n}^{2+}$ couple is highly positive (+ 1.57 V) as compared to $C{r}^{3+}/C{r}^{2+}$.
(b) Write one similarity and one difference between the chemistry of lanthanoid and actinoid elements.

Q. For octahedral Mn(ll) and tetrahedral Ni(ll) complexes, consider the following statements:
(l) Both the complexes can be high spin.
(ll) Ni(ll) complex can very rarely be of low spin.
(lll) With strong field ligands, Mn(ll) complexes can be low spin.
(lV) Aqueous solution of Mn(ll) ions is yellow in color.
The correct statements are:

1. (l), (ll) and (lll) only
2. (l), (lll) and (lV) only
3. (l) and (ll) only
4. (ll), (lll) and (lV) only

Q. (a) How would you account for the following :

(i) The chemistry of actinoids is more complicated as compared to lanthanoids.

(ii) Transition metals form complex compounds.

(b) Complete the following equation :
$2Mn{O}_4^{-}+6H^{+}+5S{O}_3^{2-}\to$

Q. chromium crytallizes in bcc lattice whose density is 7.2 g/cm^3 the edge length is 288.4 pm find avogadro number

Q. The crystal field splitting energy for octahedral $\left({\Delta }_{\circ }\right)$ and tetrahedral $\left({\Delta }_t\right)$ complexes is related as:

1. ${\Delta }_t=\frac{4}{9}{\Delta }_{\circ }$
2. ${\Delta }_t=\frac{1}{2}{\Delta }_{\circ }$
3. ${\Delta }_{\circ }=-2{\Delta }_t$
4. ${\Delta }_{\circ }=-\frac{4}{9}{\Delta }_t$

Q. The colour of the coordination compounds depends on the crystal field splitting. What will be the correct order of absorption of wavelength of light in the visible region, for the complexes, $\left[Co\right(N{H}_3{)}_6{]}^{3+},\left[Co\right(CN{)}_6{]}^{3-},\left[Co\right(H_{2}O{)}_6{]}^{3+}$ ?

1. $\left[Co\right(CN{)}_6{]}^{3-}>\left[Co\right(N{H}_3{)}_6{]}^{3+}>\left[Co\right(H_{2}O{)}_6{]}^{3+}$
2. $\left[Co\right(N{H}_3{)}_6{]}^{3+}>\left[Co\right(H_{2}O{)}_6{]}^{3+}>\left[Co\right(CN{)}_6{]}^{3-}$
3. $\left[Co\right(H_{2}O{)}_6{]}^{3+}>\left[Co\right(N{H}_3{)}_6{]}^{3+}>\left[Co\right(CN{)}_6{]}^{3-}$
4. $\left[Co\right(N{H}_3{)}_6{]}^{3+}>\left[Co\right(CN{)}_6{]}^{3-}>\left[Co\right(H_{2}O{)}_6{]}^{3+}$