p and p Overlap

Q. The correct order of strengths of back-bonding and lewis acidic strengths in Boron trihalides respectively is:

1. $B{F}_3<BC{l}_3<BB{r}_3$ and $B{F}_3<BC{l}_3<BB{r}_3$
2. $B{F}_3>BC{l}_3>BB{r}_3$ and $B{F}_3>BC{l}_3>BB{r}_3$
3. $B{F}_3>BC{l}_3>BB{r}_3$ and $B{F}_3<BC{l}_3<BB{r}_3$
4. $B{F}_3<BC{l}_3<BB{r}_3$ and $B{F}_3>BC{l}_3>BB{r}_3$

Q. Use the molecular orbital energy level diagram to show that $N_2$ would be expected to have a triple bond, $F_2$ , a single bond and $N{e}_2$, no bond

Q. A xenon compound ‘A’ upon partial hydrolysis gives $Xe{O}_2{F}_2$. The number of lone pairs of electrons present in compound A is ______. (Round off to the Nearest Integer).

Q.

Polarity in a molecule and hence the dipole moment depends primarily on electronegativity of the constituent atoms and shape of a molecule. Which of the following has the highest dipole moment?

1. $HI$
2. $C{O}_2$
3. $S{O}_2$
4. $H_{2}O$

Q. If the internuclear axis of a diatomic molecule is $z$, orbitals $p_x$ of one atom and $p_y$ of the other overlap with each other to form which of the following bonds?

1. $\delta$ bond
2. $\pi$ bond
3. $\sigma$ bond
4. No bond will be formed

Q. An example of $p\pi -p\pi$ bonding is:

1. $B{F}_3$
2. $C{O}_2$
3. $N{H}_3$
4. $C{H}_4$

Q. Assuming $z$-orbital to be the inter-nuclear axis, which of the following overlaps is incorrect?

1. $2p_y+2p_y\to \pi 2p_y$
2. $2p_z+2p_z\to \sigma 2p_z$
3. $2p_x+2p_x\to \pi 2p_x$
4. $1s+2p_y\to \pi (1s-2p_y)$

Q. Which of the following compounds contain all the carbon atoms in the same hybridisation state?

1. $H_{2}C=C=C{H}_2$
2. $H_{3}C-C\equiv C-C{H}_3$
3. $H_{2}C=C=C{H}_2$
4. $H-C\equiv C-C\equiv C-H$

Q. Which of the following is the correct prediction about observed $B-F$ bond length, in $B{F}_3$ molecule?

1. None of these
2. The bond length is more than actual because of the large difference in electronegativity value.
3. The small bond length is due to $p\pi -p\pi$ back bonding.
4. Both $\left(a\right)$ and $\left(b\right)$

Q. The molecule(s) having $p\pi -p\pi$ back bonding among the following is/are:

1. $BC{l}_3$
2. $B{F}_3$
3. $BeC{l}_2$
4. Both a and b

Q. Which of the following is the correct prediction about observed $B-F$ bond length, in $B{F}_3$ molecule?

1. The bond length is more than actual because of the large difference in electronegativity value.
2. The small bond length is due to $p\pi -p\pi$ back bonding.
3. Both $\left(a\right)$ and $\left(b\right)$
4. None of these

Q. Which of the following reactions is/are likely to be impossible :

1. $(C{H}_3{)}_{2}O+B{F}_3$
2. $(Si{H}_3{)}_{2}O+B{F}_3$
3. $(Si{H}_3{)}_{3}N+B{F}_3$
4. All are possible

Q. Main axis of a diatomic molecule is z, molecular orbital px and pz overlap to form which of the following are orbitals? a) molecular orbital b)molecular orbital c) molecular orbital d) No bond will form

Q.

Which of the following statements about overlap integrals of the various orbital is true -

1)2p>2s>2sp^3>2sp^2>2sp

2)2p>2sp^3>2sp^2>2sp>2s

3)2p>2sp>2sp^2>2sp^3>2s

4)2sp^3>2sp^2>2sp>2p>2s

Q. The molecular orbital configuration of a diatomic molecule is Its bond order is

1. 3
2. 2
3. 2.5
4. 1

Q. Strongest bond is formed by the head-on overlapping of

1. 2s and 2p orbitals
2. All of these
3. 2p and 2p oribitals
4. 2s and 2s orbitals

Q. Which of the following orbital overlap is allowed?

1. 
   
2. 
   
3. 
   
4. 
   

Q.

Predict the hybridisation of each carbon in the molecule of organic compound given below. Also indicate the total number of sigma and pi bonds in this molecule.

Q. The percentage of p character in the orbitals of P4 molecule is ? (1) 50% (2) 75% (3) 60% (4) 66.6%

Q. For oxy acid $HCl{O}_x$ if $x=y=z(x,y\text{and}z$ are natural number) then calculate the value of $(x+y+z)$, Where
$x=$ Number of $O$ atoms
$y=$ Total number of lone pairs at central atom
$z=$ Total number of Pi(π) electrons in the oxy acid.

Q. Which of the following carbonyls will have the strongest $C-O$ bond?

1. $Mn{\left(CO\right)}_6^{+}$
2. $Cr{\left(CO\right)}_6$
3. $Fe{\left(CO\right)}_5$
4. $V{\left(CO\right)}_6^{-}$

Q.

Comprehension given below is followed by some multiple choice questions. Each question has one correct option. Choose the correct option.

Molecular orbitals are formed by the overlap of atomic orbitals. Two atomic orbitals combine to form two molecular orbitals called bonding molecular orbital (BMO) and anti-bonding molecular orbital (ABMO). Energy of anti-bonding orbital is raised above the parent atomic orbitals that have combined and the energy of the bonding orbital is lowered than the parent atomic orbitals.

Energies of various molecular orbitals for elements hydrogen to nitrogen increase in the order :

$\sigma 1s<{\sigma }^{\ast }1s<\sigma 2s<{\sigma }^{\ast }2s<(\pi 2p_x\approx \pi 2p_y)<\sigma 2p_z<({\pi }^{\ast }2p_x\approx {\pi }^{\ast }2p_y)<{\sigma }^{\ast }2p_z$ and for oxygen and fluorine order of energy of molecular orbitals is given below :
$\sigma 1s<{\sigma }^{\ast }1s<\sigma 2s<{\sigma }^{\ast }2s<\sigma 2p_z<(\pi 2p_x\approx \pi 2p_y)<({\pi }^{\ast }2p_x\approx {\pi }^{\ast }2p_y)<{\sigma }^{\ast }2p_z$
Different atomic orbitals of one atom combine with those atomic orbitals of the second atom which have comparable energies and proper orientation. Further, if the overlapping is head on, the molecular orbital is called 'Sigma', $\left(\sigma \right)$ and if the overlap is lateral, the molecular orbital is called 'pi', $\left(\pi \right)$. The molecular orbitals are filled with electrons according to the same rules as followed for filling of atomic orbitals. However, the order for filling is not the same for all molecules or their ions. Bond order is one of the most important parameters to compare the strength of bonds.

1. In the formation of dioxygen from oxygen atoms 10 molecular orbitals will be formed.

2. Total number of bonding molecular orbitals will not be same as total number of anti bonding orbitals in dioxygen
3. All the molecular orbitals in the dioxygen will be completely filled

4. Number of filled bonding orbitals will be same as number of filledanti-bonding orbitals.

Q. Which is strongest Lewis acid?

1. ${BF}_3$
2. $B{Cl}_3$
3. ${BI}_3$
4. $B{Br}_3$

Q. Comprehension given below is followed by some multiple choice questions. Each question has one correct option. Choose the correct option.

Molecular orbitals are formed by the overlap of atomic orbitals. Two atomic orbitals combine to form two molecular orbitals called bonding molecular orbital (BMO) and anti-bonding molecular orbital (ABMO). Energy of anti-bonding orbital is raised above the parent atomic orbitals that have combined and the energy of the bonding orbital is lowered than the parent atomic orbitals.



Energies of various molecular orbitals for elements hydrogen to nitrogen increase in the order :

$\sigma 1s<{\sigma }^{\ast }1s<\sigma 2s<{\sigma }^{\ast }2s<(\pi 2p_x\approx \pi 2p_y)<\sigma 2p_z<({\pi }^{\ast }2p_x\approx {\pi }^{\ast }2p_y)<{\sigma }^{\ast }2p_z$ and for oxygen and fluorine order of energy of molecular orbitals is given below :
$\sigma 1s<{\sigma }^{\ast }1s<\sigma 2s<{\sigma }^{\ast }2s<\sigma 2p_z<(\pi 2p_x\approx \pi 2p_y)<({\pi }^{\ast }2p_x\approx {\pi }^{\ast }2p_y)<{\sigma }^{\ast }2p_z$
Different atomic orbitals of one atom combine with those atomic orbitals of the second atom which have comparable energies and proper orientation. Further, if the overlapping is head on, the molecular orbital is called 'Sigma', $\left(\sigma \right)$ and if the overlap is lateral, the molecular orbital is called 'pi', $\left(\pi \right)$. The molecular orbitals are filled with electrons according to the same rules as followed for filling of atomic orbitals. However, the order for filling is not the same for all molecules or their ions. Bond order is one of the most important parameters to compare the strength of bonds.

In which of the following molecules, $\sigma 2p_z$ molecular orbital is filled after $\pi 2p_x\text{and}\pi 2p_x$ molecular orbitals?

1. $F_2$
2. $O_2$
   
   
3. $N_2$
   
   
4. $N{e}_2$
   
   

Q. How many orbitals are possible in $3^{rd}$ main energy level?

1. 4
2. 3
3. 9
4. 14

Q. Which is not true about metal carbonyls?

1. Here $d\pi -p\pi$ back bonding takes place
2. Here $p\pi -p\pi$ back bonding takes place
3. Here metal acts as Lewis base as well as Lewis acid
4. Here $CO$ acts as a Lewis base as well as Lewis acid

Q. From the following $p\pi -d\pi$ back bonding cannot occur in:

1. $B{F}_3$
2. $As{F}_3$
3. $P{F}_3$
4. $O(Si{H}_3{)}_2$

Q. The p-p orbital overlapping is present in the following molecule

1. Hydrogen Chloride
2. Hydrogen
3. Chlorine
4. Hydrogen bromide

Q. Which of the following will form the sigma bond?

Q.

The electrons present in the outermost shell of an atom?