Chemical Bonding and Molecular Structure

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Identify the correct orders against the property mentioned :A. H_2O > NH_3 > CHCl_3 - dipole momentB. XeF_4 > XeO_3 > XeF_2 - number of lone pairs on central atomC. O-H > C-H > N-O - bond lengthD. N_2 > O_2 > H_2 - bond enthalpyChoose the correct ans… Answer: 1. A, D only A true: H₂O (1.85 D) > NH₃ (1.47 D) > CHCl₃ (1.04 D). B false: lone pairs on Xe are XeF₄ = 2, XeO₃ = 1, XeF₂ = 3, so th... Electronegativity, Fajan's rule, dipole moment 1 answer
Match List - I with List - IIList-I: A. XeO_3 B. XeF_2 C. XeOF_4 D. XeF_6List-II: I. sp^3d; linear II. sp^3; pyramidal III. sp^3d^3; distorted octahedral IV. sp^3d^2; square pyramidalChoose the correct answer from the options given below : Answer: 1. A-II, B-I, C-IV, D-III Key idea: count bond pairs and lone pairs on Xe. XeO₃ : 3 bonds + 1 lone pair, sp³ , pyramidal (II). XeF₂... VSEPR theory and shapes of molecules 1 answer
Given below are two statements :Statement I : A hypothetical diatomic molecule with bond order zero is quite stable.Statement II : As bond order increases, the bond length increases.In the light of the above statements, choose the most appropriate an… Answer: 2. Both Statement I and Statement II are false Key idea: bond order measures net bonding; it links to stability and bond length. Sta... Molecular orbital theory, bond order, bond length, bond energy 1 answer
Identify the correct answer. Answer: 1. Three canonical forms can be drawn for CO₃²⁻ ion. Key idea: check each statement. mathrmCO₃²⁻ : three equivalent canonical forms.... Valence bond theory, hybridization (s, p, d), resonance 1 answer
Arrange the following elements in increasing order of electronegativity:N, O, F, C, SiChoose the correct answer from the options given below: Answer: 2. Si < C < N < O < F Key idea: electronegativity increases across a period and decreases down a group. Pauling values: Si 1.8 < C 2... Electronegativity, Fajan's rule, dipole moment 1 answer
Intramolecular hydrogen bonding is present in Answer: 2. [structure: 2-nitrophenol (NO2 and OH on adjacent carbons), see figure] Key idea: intramolecular H-bonding needs the H-donor (-OH... Metallic bonding and hydrogen bonding 1 answer
Match List I with List II.List I (Molecule): A. ethane B. ethene C. carbon molecule, C_2 D. ethyneList II (Number and types of bond/s between two carbon atoms): I. one σ-bond and two π-bonds II. two π-bonds III. one σ-bond IV. one σ-bond and one π-bo… Answer: 4. A-III, B-IV, C-II, D-I Key idea: count the bond between the two carbons. Ethane H₃C-CH₃ : one σ bond (III). Ethene: one σ + one π... Valence bond theory, hybridization (s, p, d), resonance 1 answer
Match List I with List II.List I (Compound): A. NH_3 B. BrF_5 C. XeF_4 D. SF_6List II (Shape/geometry): I. Trigonal Pyramidal II. Square Planar III. Octahedral IV. Square PyramidalChoose the correct answer from the options given below: Answer: 2. A-I, B-IV, C-II, D-III Key idea: use VSEPR to get the shape of each molecule. NH₃ : 3 bond pairs + 1 lone pair gives trigonal pyr... VSEPR theory and shapes of molecules 1 answer
What fraction of one edge centred octahedral void lies in one unit cell of fcc? Answer: 4. 1/4 Key idea: An octahedral void at an edge centre is shared by the 4 unit cells meeting at that edge. An fcc cell has one octahe... Ionic bonding and lattice enthalpy 1 answer
Amongst the following, the total number of species NOT having eight electrons around central atom in its outer most shell, isNH_3, AlCl_3, BeCl_2, CCl_4, PCl_5 : Answer: 2. 3 Key idea: Count the electrons in the valence shell of the central atom. NH₃ : 8 (3 bond pairs + 1 lone pair). AlCl₃ : 6 (incomp... Kossel-Lewis approach, ionic and covalent bonds 1 answer
Intermolecular forces are forces of attraction and repulsion between interacting particles that will include :A. dipole - dipole forces.B. dipole - induced dipole forces.C. hydrogen bonding.D. covalent bonding.E. dispersion forces.Choose the most app… Answer: 4. A, B, C, E are correct. Key idea: Intermolecular forces act between molecules; covalent bonds are intramolecular. Dipole-dipole (... Metallic bonding and hydrogen bonding 1 answer
The number of σ bonds, π bonds and lone pair of electrons in pyridine, respectively are : Answer: 4. 11, 3, 1 Key idea: Count bonds in pyridine, C₅H₅N (a six-membered ring with 3 C=C/C=N double bonds). σ bonds: 6 ring bonds + 5 C-... Valence bond theory, hybridization (s, p, d), resonance 1 answer
A compound is formed by two elements A and B. The element B forms cubic close packed structure and atoms of A occupy 1/3 of tetrahedral voids. If the formula of the compound is A_xB_y, then the value of x + y is in option Answer: 2. 5 Key idea: In ccp, if B atoms number N, there are N octahedral and 2N tetrahedral voids. Take 1 unit cell: B = 4 atoms; tetrahed... Ionic bonding and lattice enthalpy 1 answer
The correct order of energies of molecular orbitals of N_2 molecule, is : Answer: 2. σ 1s<σ^* 1s<σ 2s<σ^* 2s<(π 2p_x=π 2p_y)<σ 2p_z<(π^* 2p_x=π^* 2p_y)<σ^* 2p_z Key idea: For molecules with 14 or fewer electrons (... Molecular orbital theory, bond order, bond length, bond energy 1 answer
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).Assertion (A) :In a particular point defect, an ionic solid is electrically neutral, even if few of its cations are missing from its unit cells.… Answer: 3. Both (A) and (R) are correct but (R) is not the correct explanation of (A) Key idea: missing cations with overall neutrality desc... Ionic bonding and lattice enthalpy 1 answer
Which amongst the following is incorrect statement ? Answer: 1. O₂^+ ion is diamagnetic. Key idea: write MO configurations and count unpaired electrons. O₂^+ has 15 electrons, with one electron... Molecular orbital theory, bond order, bond length, bond energy 1 answer
Amongst the following which one will have maximum 'lone pair - lone pair' electron repulsions ? Answer: 1. XeF₂ Key idea: compare the number of lone pairs on the central atom and their arrangement. XeF₂ : 3 lone pairs on Xe (trigonal bi... VSEPR theory and shapes of molecules 1 answer
Which of the following molecules is non-polar in nature ? Answer: 3. SbCl₅ Key idea: a molecule is non-polar if its bond dipoles cancel by symmetry. SbCl₅ is a symmetric trigonal bipyramid with no l... Electronegativity, Fajan's rule, dipole moment 1 answer
Right option for the number of tetrahedral and octahedral voids in hexagonal primitive unit cell are : Answer: 4. 12, 6 Key idea: in a close-packed structure with n atoms per cell, there are n octahedral voids and 2n tetrahedral voids. A hexag... Ionic bonding and lattice enthalpy 1 answer
The structures of beryllium chloride in solid state and vapour phase, are : Answer: 1. Chain and dimer, respectively Key idea: BeCl₂ is electron deficient and completes its octet by bridging. In the solid state it fo... VSEPR theory and shapes of molecules 1 answer
Match List - I with List - II.List - I : (a) PCl_5 (b) SF_6 (c) BrF_5 (d) BF_3List - II : (i) Square pyramidal (ii) Trigonal planar (iii) Octahedral (iv) Trigonal bipyramidalChoose the correct answer from the options given below. Answer: 1. (a)-(iv), (b)-(iii), (c)-(i), (d)-(ii) Key idea: use VSEPR to find shapes. PCl₅ : 5 bond pairs, trigonal bipyramidal (iv) SF₆ : 6... VSEPR theory and shapes of molecules 1 answer
BF_3 is planar and electron deficient compound. Hybridization and number of electrons around the central atom, respectively are : Answer: 3. sp² and 6 Key idea: BF₃ has three bond pairs and no lone pair on boron. Three electron domains give sp² hybridisation and trigona... Valence bond theory, hybridization (s, p, d), resonance 1 answer
Which of the following set of molecules will have zero dipole moment ? Answer: 4. Boron trifluoride, beryllium difluoride, carbon dioxide, 1,4-dichlorobenzene Zero dipole moment needs a symmetric shape where bon... Electronegativity, Fajan's rule, dipole moment 1 answer
An element has a body centered cubic (bcc) structure with a cell edge of 288 pm. The atomic radius is : Answer: 1. sqrt3/4×288 pm In a bcc unit cell atoms touch along the body diagonal. Body diagonal =sqrt3 a=4r . r=sqrt3/4a=sqrt3/4×288\ pm≈124... Metallic bonding and hydrogen bonding 1 answer

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