Chemical bonding and molecular structure class 11 questions and answers
Short Answer type
Question 1
"Atomic orbital is monocentric while a molecular orbital in polycentric". Explain
Answer
Atomic Orbital (Monocentric): An atomic orbital is associated with a single atom and describes the region around the nucleus where there is a high probability of finding an electron. Since it's linked to one nucleus, it's considered monocentric (having one center). Molecular Orbital (Polycentric): A molecular orbital, on the other hand, is formed when atomic orbitals from two or more atoms combine. This happens when atoms form bonds, such as in a molecule. The molecular orbital describes a region where electrons have a high probability of being found around multiple nuclei. Hence, it is called polycentric (having more than one center).
In essence, an atomic orbital focuses on a single nucleus (monocentric), while a molecular orbital extends over multiple nuclei (polycentric) because it spans across atoms in a molecule.
Question 2
Difference between bonding and antibonding molecular orbitals
Question 3
Use MOT to explain why $Be_2$ molecule doesn’t exist.
Question 4
Difference between sigma and pie bond.
Question 5
Give order of stability of following:-
$O_2^{2-}$, $O_2^+$, $O_2^-$, $O_2$
Question 6
Describe hybridization in $PCl_5$. Why are axial bond longer than equitorial bonds?
Question 7
Give hybridization of $CO_3^{2-}$, $AlCl_3$,$CH_4$,$C_2H_2$
Question 8
Write the Lewis dot structure of the below molecules
(i) $CH_4$
(ii) $NH_3$
(iii) $CO2$
(iv) $SO_4^{2-}$
(v)$C_2H_2$ Question 9
Which of the following is less stable and why : $H_2^+$, $H_2^-$ Question 10
What is the shape of the following molecules using VSEPR Mode?
(A)$BeCl_2$
(B)$BCl_3$
(C)$CH_4$
(D) $SiCl_4$
(E)$H_2S$
Question 11
Write the Resonance structure for
(i) $SO_3$
(ii) $NO_2$
(iii)$NO_3^-$
Answer
Question 12
Explain why the dipole moment of $NH_3$ is more than $NF_3$?
Answer
This is due to the bond moment of N-H and N-F bond.In $NH_3$, N is more electronegative then H, therefore the dipole moments of N-H bonds are in the same direction as that of the lone pair. But in $NF_3$, F is more electronegative than N, therefore the bond moments of the N-F oppose that of lone pair
Question 13
In both water and dimethyl ether ($CH_3 — Ο — CH_3$ ), oxygen atom is central atom, and has the same hybridisation, yet they have different bond angles.
Which one has greater bond angle? Give reason
Answer
Dimethyl ether will have larger bond angle. There will be more repulsion between bond pairs of CH3 groups attached in ether than between bond pairs of hydrogen atoms attached to oxygen in water. The carbon of CH3 in ether is attached to three hydrogen atoms through σ bonds and electron pairs of these bonds add to the electronic charge density on carbon atom. Hence, repulsion between two $—CH_3$ groups will be more than that between two hydrogen atoms.
Question 14
$MgCl_2$ is linear but $SnCl_2$ is angular? Explain
Long Answer Type
Question 1
Define hydrogen bonding and it types.
Question 2
(i)Discuss the significance/ applications of dipole moment.
(ii) Represent diagrammatically the bond moments and the resultant dipole moment in $CO_2$ ,$NF_3$ and $CHCl_3$
Question 3
(i)What are the guidelines to write the resonance structures of the Molecules
(ii) How do you account for the same bond length in the $O_3$ Molecules?
Question 4
Explain the concept of formation of covalent bond due to Valence Bond Theory
Question 1
The hybridization of C involved in actylene is
(a) $sp^2$
(b) $sp^3$
(c) $sp$
(d) $dsp^2$
Question 2
The percentage s-character of the hybrid orbitals in methane, ethene and ethyne are
(a) 25,50,75
(b) 25,33,50
(c) 25,33,75
(d) 100,50,25 Question 3
Which of the following has the highest boiling points?
(a)$NH_3$
(b)$PH_3$
(c)$SbH_3$
(d)$AsH_3$
Question 4
Which of the following species have the same shape?
(a) $CO_2$
(b) $CCl_4$
(c) $O_3$
(d) $NO_2^{-}$
Question 5
The type of hybridization of Carbon atom from left to right in below molecule
$CH_3-CH=C=CH-CH_3$
(a) $sp^3,sp^2,sp,sp^2,sp^3$
(b) $sp^3,sp,sp,sp^2,sp^3$
(c) $sp^3,sp^2,sp,sp^3,sp^3$
(d) $sp^3,sp^2,sp^2,sp^2,sp^3$
