NCERT Exemplar solutions for Chemistry [English] Class 11 chapter 4 - Chemical Bonding and Molecular Structure [Latest edition]

Isostructural species are those which have the same shape and hybridisation. Among the given species identify the isostructural pairs.

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?

The types of hybrid orbitals of nitrogen in \[\ce{NO^{+}2}\] , \[\ce{NO^{-}3}\] and \[\ce{NH^{+}4}\] respectively are expected to be ______.

Hydrogen bonds are formed in many compounds e.g., \[\ce{H2O, HF, NH3}\]. The boiling point of such compounds depends to a large extent on the strength of hydrogen bond and the number of hydrogen bonds. The correct decreasing order of the boiling points of above compounds is ______.

In \[\ce{PO^{3-}4}\] ion the formal charge on the oxygen atom of P – O bond is ______.

In \[\ce{NO^{-}3}\] ion, the number of bond pairs and lone pairs of electrons on nitrogen atom are ______.

Which of the following species has tetrahedral geometry?

Number of π bonds and σ bonds in the following structure is ______.

Which molecule/ion out of the following does not contain unpaired electrons?

In which of the following molecule/ion all the bonds are not equal?

In which of the following substances will hydrogen bond be strongest?

If the electronic configuration of an element is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d² 4s², the four electrons involved in chemical bond formation will be ______.

Which of the following angle corresponds to sp² hybridisation?

Stable form of A may be represented by the formula:

Stable form of C may be represented by the formula:

The molecular formula of the compound formed from \[\ce{B}\] and \[\ce{C}\] will be ______.

The bond between B and C will be ______.

Which of the following order of energies of molecular orbitals of \[\ce{N2}\] is correct?

Which of the following statement is not correct from the view point of molecular orbital theory?

Which of the following options represents the correct bond order?

The electronic configuration of the outer most shell of the most electronegative element is ______.

Amongst the following elements whose electronic configurations are given below, the one having the highest ionisation enthalpy is ______.

Which of the following have identical bond order?

(i) \[\ce{CN-}\]

(ii) \[\ce{NO+}\]

(iii) \[\ce{O^{-}2}\]

(iv) \[\ce{O^{2-}2}\]

Which of the following attain the linear structure?

(i) \[\ce{BeCl2}\]

(ii) \[\ce{NCO+}\]

(iii) \[\ce{NO2}\]

(iv) \[\ce{CS2}\]

\[\ce{CO}\] is isoelectronic with

(i) \[\ce{NO+}\]

(ii) \[\ce{N2}\]

(iii) \[\ce{Sncl2}\]

(iv) \[\ce{NO^{-}2}\]

Which of the following species have the same shape?

(i) \[\ce{CO2}\]

(ii) \[\ce{CCl4}\]

(iii) \[\ce{O3}\]

(iv) \[\ce{NO^{-}3}\]

Which of the following statements are correct about \[\ce{CO^{2-}3}\]?

(i) The hybridisation of central atom is sp³.

(ii) Its resonance structure has one \[\ce{C - O}\] single bond and two \[\ce{C = O}\] double bonds.

(iii) The average formal charge on each oxygen atom is 0.67 units.

(iv) All \[\ce{C - O}\] bond lengths are equal.

Dimagnetic species are those which contain no unpaired electrons. Which among the following are dimagnetic?

(i) \[\ce{N2}\]

(ii) \[\ce{N^{2-}2}\]

(iii) \[\ce{O2}\] 

(iv) \[\ce{O^{2-}2}\]

Species having same bond order are:

(i) \[\ce{N2}\]

(ii) \[\ce{N^{-}2}\]

(iii) \[\ce{F^{+}2}\]

(iv) \[\ce{O^{-}2}\]

Which of the following statements are not correct?

(i) \[\ce{NaCl}\] being an ionic compound is a good conductor of electricity in the solid state.

(ii) In canonical structures there is a difference in the arrangement of atoms.

(iii) Hybrid orbitals form stronger bonds than pure orbitals.

(iv) \[\ce{VSEPR}\] Theory can explain the square planar geometry of \[\ce{XeF4}\].

Explain the non-linear shape of \[\ce{H2S}\] and non-planar shape of \[\ce{PCl3}\] using valence shell electron pair repulsion theory.

Using molecular orbital theory, compare the bond energy and magnetic character of \[\ce{O^{+}2}\] and \[\ce{O^{-}2}\] species.

Explain the shape of \[\ce{BrF5}\].

Structures of molecules of two compounds are given below :

(I)	(II)

1. Which of the two compounds will have intermolecular hydrogen bonding and which compound is expected to show intramolecular hydrogen bonding.
2. The melting point of a compound depends on, among other things, the extent of hydrogen bonding. On this basis explain which of the above two compounds will show higher melting point.
3. Solubility of compounds in water depends on power to form hydrogen bonds with water. Which of the above compounds will form hydrogen bond with water easily and be more soluble in it.

Why does type of overlap given in the following figure not result in bond formation?

Explain why \[\ce{PCl5}\] is trigonal bipyramidal whereas \[\ce{IF5}\] is square pyramidal.

In both water and dimethyl ether \[\ce{(CH3 - \overset{\bullet\bullet}{\underset{\bullet\bullet}{O}} - CH3)}\], oxygen atom is central atom, and has the same hybridisation, yet they have different bond angles. Which one has greater bond angle? Give reason.

Write Lewis structure of the following compounds and show formal charge on atom.

\[\ce{HNO3}\]

Write Lewis structure of the following compounds and show formal charge on atom.

\[\ce{NO2}\]

Write Lewis structure of the following compounds and show formal charge on atom.

\[\ce{H2SO4}\]

The energy of σ2p_z molecular orbital is greater than π2p_x and π2p_y molecular orbitals in nitrogen molecule. Write the complete sequence of energy levels in the increasing order of energy in the molecule. Compare the relative stability and the magnetic behaviour of the following species :

\[\ce{N2, N^{+}2, N^{-}2, N^{2+}2}\]

What is the effect of the following processes on the bond order in \[\ce{N2}\] and \[\ce{O2}\]?

(i) \[\ce{N2 -> N^{+}2 + e-}\]

(ii) \[\ce{O2 -> O^{+}2 + e-}\]

Give reasons for the following:

Covalent bonds are directional bonds while ionic bonds are nondirectional.

Give reasons for the following:

Water molecule has bent structure whereas carbon dioxide molecule is linear.

Give reasons for the following:

Ethyne molecule is linear.

What is an ionic bond? With two suitable examples explain the difference between an ionic and a covalent bond?

Arrange the following bonds in order of increasing ionic character giving reason.

\[\ce{N - H, F - H, C - H}\] and \[\ce{O - H}\]

Explain why \[\ce{CO^{2–}3}\] ion cannot be represented by a single Lewis structure. How can it be best represented?

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.

\[\begin{array}{cc}
\phantom{.............}\ce{O}\phantom{............}\ce{O}\phantom{}\\
\phantom{.............}||\phantom{...........}//\phantom{.}\\
\ce{CH ≡ C - C - CH2 - C}\\
\phantom{........................}\backslash\\
\phantom{.............................}\ce{OH}
\end{array}\]

Group the following as linear and non-linear molecules:

\[\ce{H2O, HOCl, BeCl2, Cl2O}\]

Elements \[\ce{X, Y}\] and \[\ce{Z}\] have 4, 5 and 7 valence electrons respectively. Write the molecular formula of the compounds formed by these elements individually with hydrogen.

Elements \[\ce{X, Y}\] and \[\ce{Z}\] have 4, 5 and 7 valence electrons respectively. Which of these compounds will have the highest dipole moment?

Draw the resonating structure of ozone molecule

Draw the resonating structure of nitrate ion

Predict the shapes of the following molecules on the basis of hybridisation.

\[\ce{BCl3, CH4 , CO2, NH3}\]

All the \[\ce{C - O}\] bonds in carbonate ion \[\ce{(CO^{2-}3)}\] are equal in length. Explain.

What is meant by the term average bond enthalpy? Why is there difference in bond enthalpy of \[\ce{O - H}\] bond in ethanol \[\ce{(C2H5OH)}\] and water?

Match the species in Column I with the type of hybrid orbitals in Column II.

Match the species in Column I with the geometry/shape in Column II.

Match the species in Column I with the bond order in Column II.

Match the items given in Column I with examples given in Column II.

Match the shape of molecules in Column I with the type of hybridisation in Column II.

Assertion (A): Sodium chloride formed by the action of chlorine gas on sodium metal is a stable compound.

Reason (R): This is because sodium and chloride ions acquire octet in sodium chloride formation.

Assertion (A): Though the central atom of both \[\ce{NH3}\] and \[\ce{H2O}\] molecules are sp³ hybridised, yet \[\ce{H -N - H}\] bond angle is greater than that of \[\ce{H - O - H}\].

Reason (R): This is because nitrogen atom has one lone pair and oxygen atom has two lone pairs.

Assertion (A): Among the two \[\ce{O - H}\] bonds in \[\ce{H2O}\] molecule, the energy required to break the first \[\ce{O - H}\] bond and the other \[\ce{O - H}\] bond is the same.

Reason (R): This is because the electronic environment around oxygen is the same even after breakage of one \[\ce{O - H}\] bond.

Discuss the significance/ applications of dipole moment.

Represent diagrammatically the bond moments and the resultant dipole moment in \[\ce{CO2, NF3}\] and \[\ce{CHCl3}\].

Use the molecular orbital energy level diagram to show that \[\ce{N2}\] would be expected to have a triple bond, \[\ce{F2}\], a single bond and \[\ce{Ne2}\], no bond.

Briefly describe the valence bond theory of covalent bond formation by taking an example of hydrogen. How can you interpret energy changes taking place in the formation of dihydrogen?

Describe hybridisation in the case of \[\ce{PCl5}\] and \[\ce{SF6}\]. The axial bonds are longer as compared to equatorial bonds in \[\ce{PCl5}\] whereas in \[\ce{SF6}\] both axial bonds and equatorial bonds have the same bond length. Explain.

Discuss the concept of hybridisation. What are its different types in a carbon atom.

What is the type of hybridisation of carbon atoms marked with star.

\[\begin{array}{cc}
\phantom{.....}\ce{O}\\
\phantom{.....}||\\
\ce{\overset{∗}{C}H2 = CH - \overset{∗}{C} - O - H}
\end{array}\]

What is the type of hybridisation of carbon atoms marked with star.

\[\ce{CH3 - \overset{∗}{C}H2 - OH}\]

What is the type of hybridisation of carbon atoms marked with star.

\[\begin{array}{cc}
\phantom{..........}\ce{O}\\
\phantom{..........}||\\
\ce{CH3 - CH2 - \overset{∗}{C} - H}
\end{array}\]

What is the type of hybridisation of carbon atoms marked with star.

\[\ce{\overset{∗}{C}H3 - CH = CH - CH3}\]

What is the type of hybridisation of carbon atoms marked with star.

\[\ce{CH3 - \overset{∗}{C} ≡ CH}\]

Which of the following statements is correct?

Which of the following molecular orbitals has maximum number of nodal planes?

Which of the following pair is expected to have the same bond order?

In which of the following molecules, `σ2p_z` molecular orbital is filled after `π2p_x` and `π2p_y` molecular orbitals?