Class 11 Chemistry · 68 questions · 33 with answers
Isostructural species are those which have the same shape and hybridisation. Among the given species identify the isostructural pairs.
(ii) [BF4 and NH4 ]
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?
(iii) H2O
The types of hybrid orbitals of nitrogen in NO2 , NO3 and NH4 respectively are expected to be
(ii) sp, sp2 and sp3
Hydrogen bonds are formed in many compounds e.g., 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 :
(ii) H2O > HF > NH3
In PO4 ion the formal charge on the oxygen atom of P–O bond is
(ii) –1
In NO3 ion, the number of bond pairs and lone pairs of electrons on nitrogen atom are
(iv) 4, 0
Which of the following species has tetrahedral geometry? –
(i) BH4 –
Number of π bonds and σ bonds in the following structure is–
(iii) 5, 19
Which molecule/ion out of the following does not contain unpaired electrons? +
(iii) O2
In which of the following molecule/ion all the bonds are not equal?
(iii) C2H4
In which of the following substances will hydrogen bond be strongest?
(ii) H2O
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_____.
(iv) 3d2, 4s2
Which of the following angle corresponds to sp2 hybridisation?
(ii) 120°
Stable form of A may be represented by the formula :
(i) A
Stable form of C may be represented by the formula :
(ii) C2 41 Chemical Bonding and Molecular Structure
The molecular formula of the compound formed from B and C will be
(iv) BC3
The bond between B and C will be
(ii) Covalent
Which of the following order of energies of molecular orbitals of N2 is correct?
(i) (π2py ) < (σ2pz) < (π*2px) ≈ (π*2py )
Which of the following statement is not correct from the view point of molecular orbital theory?
(iv) The order of energies of molecular orbitals in N2 molecule is σ2s < σ* 2s < σ2pz < (π2px = π2py ) < (π* 2px = π* 2py) < σ*2pz
Which of the following options represents the correct bond order : – +
(ii) O2 < O2 < O2 – +
The electronic configuration of the outer most shell of the most electronegative element is
(i) 2s22p5
Amongst the following elements whose electronic configurations are given below, the one having the highest ionisation enthalpy is
(ii) [Ne]3s23p3
Which of the following have identical bond order? –
(i) CN +
(ii) NO –
Which of the following attain the linear structure:
(i) BeCl2
(iv) CS2
CO is isoelectronic with +
(i) NO
(ii) N2
Which of the following species have the same shape?
(iii) O3 –
(iv) NO2 2–
Which of the following statements are correct about CO3 ?
(iii) The average formal charge on each oxygen atom is 0.67 units.
(iv) All C–O bond lengths are equal. 43 Chemical Bonding and Molecular Structure
Dimagnetic species are those which contain no unpaired electrons. Which among the following are dimagnetic?
(i) N2 2–
(iv) O2
Species having same bond order are :
(iii) F2 –
(iv) O2
Which of the following statements are not correct?
(i) 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.
Explain the non linear shape of H2S and non planar shape of PCl3 using valence shell electron pair repulsion theory.
Using molecular orbital theory, compare the bond energy and magnetic + – character of O2 and O2 species.
(i) According to molecular orbital theory electronic configurations of + – O2 and O2 species are as follows : O2 : (1s) (* 1s ) (2s) (* 2s ) (2pz) (2px2 , 2p2y ) (* 2px1 ) + 2 2 2 2 2 O2 : (1s) (* 1s ) (2s) (* 2s ) (2pz) (2p2x ,2p2y ) (* 2px2 , * 2py1) – 2 2 2 2 2 + 10 − 5 5 Bond order of O2 = = = 2.5 2 2 10 − 7 3 – Bond order of O2 = = = 1.5 2 2 + – Higher bond order of O2 shows that it is more stable than O2 . Both the species have unpaired electrons. So both are paramagnetic in nature.
Explain the shape of BrF5.
Structures of molecules of two compounds are given below :
(a) Which of the two compounds will have intermolecular hydrogen bonding and which compound is expected to show intramolecular hydrogen bonding.
(b) 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.
(c) 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 PCl5 is trigonal bipyramidal whereas IF5 is square pyramidal.
In both water and dimethyl ether (CH3 — Ο — 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.
[Hint : 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 —CH3 groups will be more than that between two hydrogen atoms.] IV. Matching Type 52. (i) → (c) (ii) → (a) (iii) → (e) (iv) → (d) 53. (i) → (e) (ii) → (a) (iii) → (b) (iv) → (c) 54. (i) → (c) (ii) → (d) (iii) → (a) (iv) → (b) 55. (i) → (d) (ii) → (e) (iii) → (b) (iv) → (a) 56. (i) → (c) (ii) → (a) (iii) → (b) V. Assertion and Reason Type 57. (i) 58. (i) 59. (iv) 65. (i) 66. (ii) 67. (ii) 68. (iii)
Write Lewis structure of the following compounds and show formal charge on each atom. HNO3, NO2, H2SO4
The energy of 2pz molecular orbital is greater than 2px and 2py 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 : + – 2+ N2, N2 , N2 , N2
What is the effect of the following processes on the bond order in N2 and O2? N2 N2 + e– O2 O2 + e– + +
Give reasons for the following :
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. N—H, F—H, C—H and O—H 2–
Explain why CO3 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.
Group the following as linear and non-linear molecules : H2O, HOCl, BeCl2, Cl2O
Elements X, Y and Z have 4, 5 and 7 valence electrons respectively.
Draw the resonating structure of
Predict the shapes of the following molecules on the basis of hybridisation. BCl3, CH4, CO2, NH3 2–
All the C—O bonds in carbonate ion (CO3 ) are equal in length. Explain.
What is meant by the term average bond enthalpy? Why is there difference in bond enthalpy of O—H bond in ethanol (C2H5OH) and water?
Match the species in Column I with the type of hybrid orbitals in Column II. Column I Column II (i) SF4
Match the species in Column I with the geometry/shape in Column II. Column I Column II + (i) H3O
Match the species in Column I with the bond order in Column II. Column I Column II (i) NO
Match the items given in Column I with examples given in Column II. Column I Column II (i) Hydrogen bond
Match the shape of molecules in Column I with the type of hybridisation in Column II. Column I Column II (i) Tetrahedral
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. 47 Chemical Bonding and Molecular Structure (i) A and R both are correct, and R is the correct explanation of A. (ii) A and R both are correct, but R is not the correct explanation of A. (iii) A is true but R is false. (iv) A and R both are false.
Assertion (A): Though the central atom of both NH3 and H2O molecules are sp3 hybridised, yet H–N–H bond angle is greater than that of H–O–H.
Reason (R): This is because nitrogen atom has one lone pair and oxygen atom has two lone pairs. (i) A and R both are correct, and R is the correct explanation of A. (ii) A and R both are correct, but R is not the correct explanation of A. (iii) A is true but R is false. (iv) A and R both are false.
Assertion (A): Among the two O–H bonds in H2O molecule, the energy required to break the first O–H bond and the other O–H bond is the same.
Reason (R): This is because the electronic environment around oxygen is the same even after breakage of one O–H bond. (i) A and R both are correct, and R is correct explanation of A. (ii) A and R both are correct, but R is not the correct explanation of A. (iii) A is true but R is false. (iv) A and R both are false.
Use the molecular orbital energy level diagram to show that N2 would be expected to have a triple bond, F2, a single bond and 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 PCl5 and SF6. The axial bonds are longer as compared to equatorial bonds in PCl5 whereas in SF6 both axial bonds and equatorial bonds have the same bond length. Explain.
(i) Discuss the concept of hybridisation. What are its different types in a carbon atom. (ii) What is the type of hybridisation of carbon atoms marked with star.
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, σ2pz molecular orbital is filled after π2px and π2py molecular orbitals?