Valence Bond Theory

Q. The increasing order of magnetic moment values of the given compounds is:
$\left(I\right)\left[Fe\right(CN{)}_6{]}^{4-}$
$\left(II\right)\left[Fe\right(CN{)}_6{]}^{3-}$
$\left(III\right)\left[Cr\right(N{H}_3{)}_6{]}^{3+}$
$\left(IV\right)\left[Ni\right(H_{2}O{)}_6{]}^{2+}$

1. $I<II<III<IV$
2. $IV<III<II<I$
3. $II<III<I<IV$
4. $I<II<IV<III$

Q. According to Lewis theory the ligands are

1. Acidic in nature
2. Basic in nature
3. Neither acidic nor basic
4. Some are acidic some are basic

Q. The geometry of $\left[Ni\right(CO{)}_4]$ and $[NiC{l}_4{]}^{2-}$ are respectively:

1. Both are square planar
2. Tetrahedral and square planar
3. Both are tetrahedral
4. Square planar and tetrahedral

Q. The complex ${\left[Ni{\left(CN\right)}_4\right]}^{2-}$ is diamagnetic and the complex ${\left[NiC{l}_4\right]}^{2-}$ is paramagnetic. What can you conclude about their molecular geometries?

1. Both complex have square planar geometries
2. Both complexes have tetrahedral geometries
3. ${\left[NiC{l}_4\right]}^{2-}$ has a square planar geometry while ${\left[Ni\right(CN)}_4{]}^{2-}$ has a tetrahedral geometry
4. ${\left[NiC{l}_4\right]}^{2-}$ has a tetrahedral geometry while ${\left[Ni{\left(CN\right)}_4\right]}^{2-}$ has a square planar geometry

Q.

According to valence bond theory, a bond between two atoms is formed when

1. half-filled atomic orbitals overlap

2. fully-filled atomic orbitals overlap

3. non-bonding atomic orbitals overlap

4. electrons of the two atoms overlap

Q. In the complex ion $M{L}_6^{n+},M^{n+}$ has four d-electrons and L is a strong field neutral ligand. According to crystal field theory, the magnetic properties of the complex ion correspond to how many unpaired electrons?

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

Q. The no. of unpaired electrons in the complex $[Co{F}_6{]}^{3-}$ is

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

Q. Match Column-I with Column-II:
$\begin{array}{cc}\text{Column-I}& \text{Column-II}\\ \text{a.}{\left[Ni\right(CN{)}_4]}^{2-}& \text{p.}{d}^{2}s{p}^3\\ \text{b.}\left[Ni\right(CO{)}_4]& \text{q.}s{p}^3{d}^2\\ \text{c.}{\left[Co\right(en{)}_3]}^{3+}& \text{r.}ds{p}^2\\ \text{d.}{\left[Co\right(Br{)}_{3}C{l}_3]}^{3-}& \text{s.}s{p}^3\\ & \text{t. Inner orbital complex}\\ & \text{u. Outer orbital complex}\end{array}$

1. $(a-r,t),(b-s,u)$
   $(c-p,t),(d-p,t)$
2. $(a-s,t),(b-r,u)$
   $(c-p,t),(d-p,t)$
3. $(a-r,t),(b-s,u)$
   $(c-q,t),(d-p,t)$
4. $(a-s,t),(b-s,u)$
   $(c-q,u),(d-q,u)$

Q. The ratio of $\sigma$- to $\pi$-bonds in benzene is .

1. 2
2. 4
3. 6

Q. Arrange the following cobalt complexes in the order of increasing crystal field stabilisation energy (CFSE) value.

Complexes :
A . ${\left[Co{F}_6\right]}^{3-}$
B . ${\left[Co{\left(H_{2}O\right)}_6\right]}^{2+}$
C . ${\left[Co{\left(N{H}_3\right)}_6\right]}^{3+}$
D . ${\left[Co{\left(en\right)}_3\right]}^{3+}$

Choose the correct option :

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1. C < D < B < A
2. A < B < C < D
3. B < C < D < A
4. B < A < C < D

Q. The hybridisation of Fe in $[Fe{F}_6{]}^{3-}$ is $s{p}^3{d}^2$, the number of unpaired electrons present is

1. 2
2. 4
3. 5
4. 1

Q. $\left[Cu\right(N{H}_3{)}_4{]}^{2+}$ shows the following hybridization

1. $ds{p}^2$
2. $s{p}^{3}d$
3. $ds{p}^3$
4. $s{p}^3$

Q. $\left[Fe\right(CN{)}_6{]}^{3\ominus }$ has a magnetic moment of 1.73 BM. Thus hybridization of Fe is

1. $d^{2}s{p}^3$
2. $s{p}^3{d}^2$
3. $ds{p}^2$
4. $s{p}^3$

Q. In V.B.T., the idea of hybridization was required to explain which of the following facts:

1. The equivalence of the bonds in most of the compounds
2. The stereochemistry of the molecules
3. The better overlapping of the orbitals
4. None of these

Q. According to molecular orbital theory, which of the following statements is(are) correct?

1. $O_2^{2+}$ is expected to have a longer bond length than $O_2$
2. $N_2^{+}$ and $N_2^{-}$ have the same bond order
3. $H{e}_2^{+}$ has the same energy as two isolated $He$ atoms
4. $C_2^{2-}$ is expeced to be diamagnetic

Q. If $H_{2}O$ is a weak field ligand, the no. of unpaired electrons in $\left[Mn\right(H_{2}O{)}_6{]}^{2+}$ is

1. 2
2. 3
3. 4
4. 5

Q. The structure of diborane contains:

1. four $2C-2e$ bonds and two $3C-2e$ bonds
2. four $2C-2e$ bonds and four $3C-2e$ bonds
3. two $2C-2e$ bonds and two $3C-2e$ bonds
4. two $2C-2e$ bonds and four $3C-2e$ bonds

Q.

Which among the following are the repulsive forces acting between two atoms A and B?
If $e_A$, $e_B$ represents electrons of atom A and B respectively and $N_A$, $N_B$ represents nuclei of atom A and B respectively.

1. $e_A-e_B$
2. $N_A-N_B$
3. $N_A-e_B$
4. $N_B-e_A$

Q. After np obitals are filled, the next orbital to be filled will be

1. (n + 1)s
2. (n+2)p
3. (n+1)d
4. (n+2)s

Q. Which one of the following complex species does not obey the $EAN$ rule?

1. $\left[Cu\right(CN{)}_4{]}^{3-}$
2. $\left[Cr\right(N{H}_3{)}_6{]}^{3+}$
3. $\left[Fe\right(CN{)}_6{]}^{4-}$
4. $\left[Ni\right(CO{)}_4]$

Q. The coordination no. of copper in cuprammonium sulphate is

1. 2
2. 6
3. 4
4. 8

Q.

An $A{B}_2$ type structure is found in

1. $NaCl$

2. $A{l}_2{O}_3$

3. $Ca{F}_2$

4. $N_{2}O$

Q.

Addition of excess aqueous ammonia to a pink coloured aqueous solution of $MC{l}_2.H_{2}O\left(x\right)andN{H}_{4}Cl$ gives an octahedral complex Y in the presence of air. In aqueous solution, complex Y behaves as 1:3 electrolyte. The reaction of X with excess HCl at room temperature results in the formation of a blue coloured complex Z. The calculated spin only magnetic moment of X and Z is 3.87 B.M., whereas it is zero for complex Y.
Among the following options, which statemet(s) is (are) correct?

1. The hybridization of the central metal ion in Y is $d^{2}s{p}^3$

2. Addition of silver nitrate to Y gives only two equivalents of silver chloride

3. When X and Z are in equilibrium at $0^{\circ },$ the colour of the solution is pink

4. Z is a tetrahedral complex
   

Q. Which of the following overlaps gives a $\sigma$ bond with x as the internuclear axis?

1. $p_z$ and $p_z$
2. s and $p_z$
3. s and $p_x$
4. $d_{x^2-y^2}$ and $d_{x^2-y^2}$

Q. Which of the following has square planar geometry?

1. $[CoC{l}_4{]}^{2-}$
2. $[FeC{l}_4{]}^{2-}$
3. $[NiC{l}_4{]}^{2-}$
4. $[PtC{l}_4{]}^{2-}$

Q. Addition of excess aqueous ammonia to a pink coloured aqueous solution of $MC{l}_2.6H_{2}O\left(X\right)$ and $N{H}_{4}Cl$ gives an octahedral complex Y in the presence of air. In aqueous solution, complex Y behaves as 1 :3 electrolyte. The reaction of X with excess $HCl$ at room temperature results in the formation of a blue coloured complex Z. The calculated spin only magnetic moment of X and Z is 3.87 B.M., whereas it is zero for the complex Y. Among the following options, which statement(s) is/are correct?

1. The hybridization of the central metal ion in Y is $d^{2}s{p}^3$
2. Z is a tetrahedral complex
3. Addition of silver nitrate to Y gives only two equivalents of silver chloride
4. When X and Z are in equilibrium at $0^{\circ }C$, the colour of the solution is pink

Q. According to molecular orbital theory, which of the following statements is(are) correct?

1. $H{e}_2^{+}$ has the same energy as two isolated $He$ atoms
2. $O_2^{2+}$ is expected to have a longer bond length than $O_2$
3. $C_2^{2-}$ is expeced to be diamagnetic
4. $N_2^{+}$ and $N_2^{-}$ have the same bond order

Q. What would be the product formed when 1 - bromo - 3 - chlorocyclobutane reacts with two equivalents of metallic sodium in ether ?

Q. Value of CFSE, in tetrahedral complex having $3d^4$ configuration of metal ion, surrounded by weak field ligands, will be

1. $+\frac{2}{5}{\Delta }_t$
2. $+\frac{3}{5}{\Delta }_t$
3. $-\frac{2}{5}{\Delta }_t$
4. $-\frac{4}{5}{\Delta }_t$

Q. Consider the coordination compound, $N{a}_2\left[Pt\right(CN{)}_4]$. The lewis base is

1. $C{N}^{-}$
2. $\left[Pt\right(CN{)}_4{]}^{2-}$
3. $N{a}^{+}$
4. $P{t}^{2+}$