Here below some basic MCQ’s about “Coordination compound” which is well explained for exam practice. Let’s check one by one.
1. Which of the following is the correct IUPAC name for the compound CH3CH2CH2OH?
a) Propanol
b) Ethanol
c) Butanol
d) Methanol
Answer: a) Propanol
Explanation: The compound has three carbon atoms and an alcohol group (-OH). According to IUPAC nomenclature, the parent chain is propane, and the suffix “ol” is added to indicate the presence of the -OH group. Thus, the name is propanol.
2. Which of the following compounds exhibits hydrogen bonding?
a) CH4
b) HCl
c) H2O
d) CCl4
Answer: c) H2O
Explanation: Water (H2O) can form hydrogen bonds due to the highly electronegative oxygen atom and the presence of hydrogen atoms. Hydrogen bonds occur when hydrogen is attached to highly electronegative atoms like oxygen, nitrogen, or fluorine.
3. What is the hybridization of carbon in methane (CH4)?
a) sp
b) sp2
c) sp3
d) dsp3
Answer: c) sp3
Explanation: In methane (CH4), the central carbon atom forms four single bonds with hydrogen atoms. To accommodate these four bonds, carbon undergoes sp3 hybridization, where one s orbital and three p orbitals combine to form four equivalent sp3 hybrid orbitals.
4. Which of the following molecules has a trigonal planar structure?
a) BF3
b) CH4
c) NH3
d) H2O
Answer: a) BF3
Explanation: Boron trifluoride (BF3) has three bonding pairs of electrons around the central boron atom, which results in a trigonal planar structure with a bond angle of 120°. There are no lone pairs on the boron atom, making the geometry trigonal planar.
5. What type of bonding is present in sodium chloride (NaCl)?
a) Covalent bond
b) Ionic bond
c) Metallic bond
d) Coordinate bond
Answer: b) Ionic bond
Explanation: Sodium (Na) donates one electron to chlorine (Cl) to form Na+ and Cl− ions, which are held together by electrostatic forces of attraction. This type of bond is called an ionic bond.
6. Which of the following compounds has a bent or V-shaped molecular geometry?
a) CO2
b) H2O
c) BeCl2
d) BF3
Answer: b) H2O
Explanation: Water (H2O) has two lone pairs of electrons on the oxygen atom and two bond pairs. The repulsion between the lone pairs causes the bond angle to reduce, giving the molecule a bent or V-shaped geometry with a bond angle of approximately 104.5°.
7. Which type of hybridization is present in ethylene (C2H4)?
a) sp
b) sp2
c) sp3
d) sp3d
Answer: b) sp2
Explanation: In ethylene (C2H4), each carbon atom forms three sigma bonds (two with hydrogen and one with the other carbon atom). The carbon atoms are sp2 hybridized, where one s orbital and two p orbitals mix to form three sp2 hybrid orbitals, leaving one unhybridized p orbital that forms a π bond.
8. Which of the following is an example of a polar covalent bond?
a) H-H
b) O=O
c) H-F
d) Cl-Cl
Answer: c) H-F
Explanation: In the H-F molecule, fluorine is much more electronegative than hydrogen, causing a significant difference in electronegativity. As a result, the electron pair is shared unequally, creating a polar covalent bond.
9. Which bond angle is closest to that found in a molecule with tetrahedral geometry?
a) 90°
b) 109.5°
c) 120°
d) 180°
Answer: b) 109.5°
Explanation: A tetrahedral molecule, like methane (CH4), has four bonding pairs of electrons that are equally spaced around the central atom. The bond angle between these bonds is 109.5°.
10. Which of the following molecules has a dipole moment?
a) CO2
b) CH4
c) NH3
d) BF3
Answer: c) NH3
Explanation: Ammonia (NH3) has a trigonal pyramidal structure with a lone pair of electrons on nitrogen. Due to this asymmetric distribution of electrons, NH3 has a net dipole moment. The lone pair-bond pair repulsion gives the molecule polarity.
12. What is the bond order of O2 molecule in its ground state?
a) 1
b) 2
c) 3
d) 0
Answer: b) 2
Explanation: The bond order can be calculated by using molecular orbital theory. For O2, the bond order is given by the formula:
Bond order = (Number of bonding electrons – Number of anti-bonding electrons) / 2.
For O2, the bond order comes out to be 2, indicating a double bond between the oxygen atoms.
13. Which of the following statements is true for carbon dioxide (CO2)?
a) It has a bent shape
b) It has a linear shape
c) It has a pyramidal shape
d) It has a square planar shape
Answer: b) It has a linear shape
Explanation: CO2 has two double bonds between the carbon and oxygen atoms, and no lone pairs on the central carbon atom. The molecule has a linear shape with a bond angle of 180°.
14. Which of the following compounds exhibits sp hybridization?
a) BeCl2
b) BF3
c) CH4
d) NH3
Answer: a) BeCl2
Explanation: In BeCl2, beryllium forms two bonds with chlorine. To accommodate these bonds, beryllium undergoes sp hybridization, resulting in a linear structure.
15. Which of the following molecules does not have a permanent dipole moment?
a) H2O
b) CH4
c) NH3
d) HCl
Answer: b) CH4
Explanation: Methane (CH4) is a symmetrical molecule with a tetrahedral geometry, and the dipole moments of the C-H bonds cancel each other out. Hence, CH4 does not have a permanent dipole moment.
16. The bond angle in NH3 is less than 109.5° because:
a) Lone pairs repel bonding pairs more strongly than bonding pairs repel each other.
b) NH3 has no lone pairs.
c) NH3 has a square planar geometry.
d) The bond angle in NH3 is exactly 109.5°.
Answer: a) Lone pairs repel bonding pairs more strongly than bonding pairs repel each other.
Explanation: In ammonia (NH3), the nitrogen atom has one lone pair of electrons and three bond pairs. The lone pair exerts greater repulsion on the bonding pairs, reducing the bond angle to approximately 107°.
17. Which of the following types of bonds is present in the ammonium ion (NH4+)?
a) Ionic bond
b) Covalent bond
c) Dative bond
d) Metallic bond
Answer: c) Dative bond
Explanation: In the ammonium ion (NH4+), the nitrogen atom donates a lone pair of electrons to form a bond with a proton (H+), creating a dative or coordinate bond. Additionally, the other bonds are regular covalent bonds.
18. The number of sigma (σ) and pi (π) bonds in ethyne (C2H2) are:
a) 3 sigma and 1 pi bond
b) 2 sigma and 2 pi bonds
c) 3 sigma and 2 pi bonds
d) 1 sigma and 3 pi bonds
Answer: c) 3 sigma and 2 pi bonds
Explanation: Ethyne (C2H2) has a triple bond between the two carbon atoms. A triple bond consists of 1 sigma bond and 2 pi bonds. Additionally, each carbon forms a sigma bond with a hydrogen atom. Therefore, there are 3 sigma bonds and 2 pi bonds in total.
19. Which of the following molecules has a non-zero dipole moment?
a) CO2
b) CHCl3
c) CCl4
d) BF3
Answer: b) CHCl3
Explanation: CHCl3 (chloroform) has a tetrahedral structure, but the asymmetrical arrangement of atoms (one hydrogen and three chlorine atoms) results in a net dipole moment. Other options like CO2 and CCl4 are symmetrical and have no net dipole moment.
20. The shape of the SF6 molecule is:
a) Tetrahedral
b) Octahedral
c) Square planar
d) Trigonal bipyramidal
Answer: b) Octahedral
Explanation: Sulfur hexafluoride (SF6) has six bonding pairs of electrons around the central sulfur atom. These six pairs arrange themselves in an octahedral geometry, with bond angles of 90°.
21. Which of the following exhibits resonance?
a) CH4
b) H2O
c) O3
d) NH3
Answer: c) O3
Explanation: Ozone (O3) exhibits resonance, as it can be represented by two equivalent Lewis structures in which the placement of the double bond and single bond between the oxygen atoms alternates.
22. Which of the following molecules has sp2 hybridization at the central atom?
a) C2H2
b) C2H4
c) C2H6
d) CH4
Answer: b) C2H4
Explanation: In ethylene (C2H4), each carbon atom forms three sigma bonds (two with hydrogen and one with another carbon atom) and one π bond. Therefore, the carbon atoms are sp2 hybridized.
23. The geometry of a molecule with three bonding pairs and one lone pair on the central atom is:
a) Linear
b) Tetrahedral
c) Trigonal pyramidal
d) Square planar
Answer: c) Trigonal pyramidal
Explanation: A molecule with three bonding pairs and one lone pair, such as NH3, adopts a trigonal pyramidal geometry due to the lone pair-bond pair repulsion, which distorts the shape from being tetrahedral.
24. Which of the following is the correct IUPAC name of the compound CH3CH(CH3)CH2CH3?
a) 3-methylbutane
b) 2-methylbutane
c) Isopentane
d) 1-methylpropane
Answer: b) 2-methylbutane
Explanation: The longest chain contains four carbon atoms (butane), and a methyl group is attached to the second carbon atom. Hence, the correct IUPAC name is 2-methylbutane.
25. Which of the following compounds has the highest bond order?
a) N2
b) O2
c) F2
d) NO
Answer: a) N2
Explanation: Nitrogen (N2) has a bond order of 3 (a triple bond), while oxygen (O2) has a bond order of 2, fluorine (F2) has a bond order of 1, and nitric oxide (NO) has a bond order between 2 and 3. Hence, N2 has the highest bond order.
26. Which of the following molecules has sp3 hybridization at the central atom?
a) C2H2
b) C2H4
c) CH4
d) CO2
Answer: c) CH4
Explanation: In methane (CH4), carbon forms four sigma bonds with four hydrogen atoms. Carbon undergoes sp3 hybridization to form four equivalent sp3 hybrid orbitals, resulting in a tetrahedral geometry.
27. The bond angle in water (H2O) is approximately:
a) 90°
b) 104.5°
c) 109.5°
d) 120°
Answer: b) 104.5°
Explanation: In water, the oxygen atom has two lone pairs and two bond pairs. The lone pair-lone pair repulsion causes the bond angle to reduce from the ideal tetrahedral angle of 109.5° to about 104.5°, giving water its bent shape.
28. Which of the following is the correct IUPAC name of the compound CH3CH2COOH?
a) Ethanoic acid
b) Propanoic acid
c) Butanoic acid
d) Methanoic acid
Answer: b) Propanoic acid
Explanation: The compound has three carbon atoms, with the carboxyl group (-COOH) attached to the first carbon atom. Therefore, the correct IUPAC name is propanoic acid.
29. Which of the following has a bond order of 1?
a) O2
b) H2
c) F2
d) N2
Answer: c) F2
Explanation: In fluorine (F2), the bond order is 1, indicating a single bond between the two fluorine atoms. This is because each fluorine atom shares one electron with the other to complete its octet.
30. Which of the following molecules has a trigonal pyramidal shape?
a) BF3
b) H2O
c) NH3
d) CH4
Answer: c) NH3
Explanation: Ammonia (NH3) has three bonding pairs and one lone pair of electrons around the nitrogen atom, which gives it a trigonal pyramidal shape. The lone pair-bond pair repulsion slightly reduces the bond angle from 109.5°.
31. The correct IUPAC name of CH3CH2CH=CH2 is:
a) 1-butene
b) 2-butene
c) 1-propene
d) 2-propene
Answer: a) 1-butene
Explanation: The compound is a four-carbon chain (butene) with a double bond between the first and second carbon atoms. The correct IUPAC name is 1-butene.
32. Which of the following types of bonds is the strongest?
a) Ionic bond
b) Covalent bond
c) Hydrogen bond
d) Van der Waals forces
Answer: a) Ionic bond
Explanation: Ionic bonds are generally stronger than covalent bonds, hydrogen bonds, and Van der Waals forces because of the strong electrostatic attraction between oppositely charged ions.
33. The number of sigma (σ) bonds in benzene is:
a) 3
b) 6
c) 12
d) 9
Answer: c) 12
Explanation: In benzene (C6H6), there are six C-H sigma bonds and six C-C sigma bonds, making a total of 12 sigma bonds.
34. Which of the following has a planar structure?
a) CH4
b) NH3
c) C2H4
d) H2O
Answer: c) C2H4
Explanation: Ethylene (C2H4) has a planar structure due to the sp2 hybridization of the carbon atoms, where the π bond restricts the rotation around the carbon-carbon bond, making the entire molecule planar.
35. Which of the following molecules contains both ionic and covalent bonds?
a) HCl
b) NH4Cl
c) H2O
d) CH4
Answer: b) NH4Cl
Explanation: In ammonium chloride (NH4Cl), the ammonium ion (NH4+) forms covalent bonds within itself, and the bond between the ammonium ion and chloride ion is ionic. Therefore, NH4Cl contains both ionic and covalent bonds.
36. Which of the following compounds exhibits coordinate bonding?
a) NaCl
b) NH4+
c) CH4
d) HCl
Answer: b) NH4+
Explanation: In the ammonium ion (NH4+), nitrogen donates a lone pair of electrons to bond with an H+ ion, forming a coordinate (dative) bond.
37. The bond angle in a molecule of BF3 is:
a) 90°
b) 120°
c) 109.5°
d) 180°
Answer: b) 120°
Explanation: Boron trifluoride (BF3) has a trigonal planar geometry due to sp2 hybridization. The bond angles between the fluorine atoms are 120°.
38. Which of the following molecules has no dipole moment?
a) H2O
b) NH3
c) CH4
d) HCl
Answer: c) CH4
Explanation: Methane (CH4) is a symmetrical tetrahedral molecule, and the dipoles of the C-H bonds cancel each other out, resulting in a net dipole moment of zero.
39. Which of the following species is paramagnetic?
a) O2
b) N2
c) CO
d) F2
Answer: a) O2
Explanation: Molecular oxygen (O2) is paramagnetic due to the presence of unpaired electrons in its molecular orbitals, as predicted by molecular orbital theory.
40. Which of the following molecules has a square planar structure?
a) SF6
b) XeF4
c) PCl5
d) CH4
Answer: b) XeF4
Explanation: Xenon tetrafluoride (XeF4) has four bonding pairs and two lone pairs around the central xenon atom, resulting in a square planar structure.
41. Which of the following is an example of a molecule with sp hybridization?
a) BeCl2
b) BF3
c) CH4
d) NH3
Answer: a) BeCl2
Explanation: In beryllium chloride (BeCl2), the central beryllium atom forms two sigma bonds and has no lone pairs, leading to sp hybridization and a linear structure.
42. The shape of PCl5 is:
a) Trigonal planar
b) Octahedral
c) Tetrahedral
d) Trigonal bipyramidal
Answer: d) Trigonal bipyramidal
Explanation: Phosphorus pentachloride (PCl5) has five bonding pairs and no lone pairs, resulting in a trigonal bipyramidal shape with bond angles of 90° and 120°.
43. Which of the following is an example of a resonance structure?
a) NH3
b) H2O
c) O3
d) CH4
Answer: c) O3
Explanation: Ozone (O3) has two equivalent resonance structures, where the position of the double bond and single bond between oxygen atoms alternates.
44. Which of the following molecules has a bond angle closest to 109.5°?
a) H2O
b) NH3
c) CH4
d) CO2
Answer: c) CH4
Explanation: Methane (CH4) has a tetrahedral geometry with bond angles of 109.5°.
45. Which of the following molecules is nonpolar despite having polar bonds?
a) HCl
b) CO2
c) H2O
d) NH3
Answer: b) CO2
Explanation: Carbon dioxide (CO2) is linear and symmetrical, and although the C=O bonds are polar, their dipole moments cancel each other out, making CO2 a nonpolar molecule.
46. Which of the following statements is correct about the bond in HCl?
a) It is purely covalent
b) It is purely ionic
c) It is polar covalent
d) It has a coordinate bond
Answer: c) It is polar covalent
Explanation: The bond in HCl is polar covalent because there is a difference in electronegativity between hydrogen and chlorine, leading to unequal sharing of electrons.
47. Which of the following molecules has a bent shape?
a) CO2
b) CH4
c) H2O
d) BF3
Answer: c) H2O
Explanation: Water (H2O) has two lone pairs on oxygen, which cause repulsion and result in a bent shape with a bond angle of about 104.5°.
48. The hybridization of the carbon atom in CO2 is:
a) sp
b) sp2
c) sp3
d) None of the above
Answer: a) sp
Explanation: In carbon dioxide (CO2), the carbon atom forms two double bonds, which involves sp hybridization, resulting in a linear geometry.
49. The number of pi bonds in benzene (C6H6) is:
a) 3
b) 6
c) 9
d) 12
Answer: a) 3
Explanation: Benzene has three alternating double bonds, each containing one pi bond. Thus, there are a total of 3 pi bonds in benzene.
50. Which of the following exhibits hydrogen bonding?
a) CH4
b) HCl
c) HF
d) CCl4
Answer: c) HF
Explanation: Hydrogen fluoride (HF) exhibits hydrogen bonding due to the large electronegativity difference between hydrogen and fluorine.
51. Which of the following molecules is linear?
a) H2O
b) NH3
c) C2H2
d) SO2
Answer: c) C2H2
Explanation: Ethyne (C2H2) is a linear molecule due to sp hybridization of the carbon atoms, with a bond angle of 180°.
52. In which of the following molecules are all atoms sp2 hybridized?
a) CH4
b) BF3
c) C2H6
d) NH3
Answer: b) BF3
Explanation: In boron trifluoride (BF3), the boron atom and all the fluorine atoms are sp2 hybridized, resulting in a trigonal planar geometry.
53. Which of the following molecules has a seesaw shape?
a) SF4
b) PCl5
c) XeF4
d) CH4
Answer: a) SF4
Explanation: In sulfur tetrafluoride (SF4), the central sulfur atom has four bonding pairs and one lone pair, resulting in a seesaw shape according to VSEPR theory.
54. Which of the following species is diamagnetic?
a) O2
b) NO
c) N2
d) B2
Answer: c) N2
Explanation: Molecular nitrogen (N2) is diamagnetic because all of its electrons are paired, while O2 and NO have unpaired electrons and are paramagnetic.
55. The formal charge on the oxygen atom in the carbonate ion (CO3^2-) is:
a) 0
b) -1
c) +1
d) -2
Answer: a) 0
Explanation: In the carbonate ion, the formal charge on each oxygen atom is 0, as the charge is delocalized over the resonance structures of the ion.
56. Which of the following species has a bond order of 2.5?
a) O2
b) CO
c) NO
d) N2
Answer: c) NO
Explanation: Nitric oxide (NO) has a bond order of 2.5, as it has an odd number of electrons, with one unpaired electron in a bonding molecular orbital.
57. Which of the following exhibits sp3d hybridization?
a) PCl5
b) SF6
c) XeF4
d) CH4
Answer: a) PCl5
Explanation: Phosphorus in PCl5 undergoes sp3d hybridization, resulting in a trigonal bipyramidal structure with 90° and 120° bond angles.
58. Which of the following has the smallest bond angle?
a) CH4
b) NH3
c) H2O
d) CO2
Answer: c) H2O
Explanation: Water (H2O) has the smallest bond angle of approximately 104.5° due to the strong lone pair-lone pair repulsion, compared to NH3 (107°), CH4 (109.5°), and CO2 (180°).
59. Which of the following molecules has a square pyramidal geometry?
a) SF6
b) PCl5
c) IF5
d) XeF4
Answer: c) IF5
Explanation: In iodine pentafluoride (IF5), the central iodine atom has five bonding pairs and one lone pair, resulting in a square pyramidal geometry.
60. The correct IUPAC name of the compound (CH3)2CHCH2CH3 is:
a) 3-methylpentane
b) 2-methylpentane
c) 2-methylbutane
d) 3-methylbutane
Answer: c) 2-methylbutane
Explanation: The longest chain contains four carbon atoms, and a methyl group is attached to the second carbon atom. Therefore, the correct IUPAC name is 2-methylbutane.
61. Which of the following molecules exhibits resonance?
a) CH4
b) H2O
c) NO3^-
d) NH3
Answer: c) NO3^-
Explanation: The nitrate ion (NO3^-) exhibits resonance, as it can be represented by multiple Lewis structures with delocalized electrons.
62. The hybridization of xenon in XeF4 is:
a) sp3
b) sp3d
c) sp3d2
d) sp2
Answer: c) sp3d2
Explanation: In xenon tetrafluoride (XeF4), the xenon atom undergoes sp3d2 hybridization, resulting in a square planar geometry.
63. Which of the following compounds contains both sigma and pi bonds?
a) H2O
b) CO2
c) CH4
d) CCl4
Answer: b) CO2
Explanation: In carbon dioxide (CO2), each carbon-oxygen bond contains both a sigma bond and a pi bond due to the double bonds between carbon and oxygen.
64. Which of the following molecules is polar?
a) BF3
b) CH4
c) H2O
d) CCl4
Answer: c) H2O
Explanation: Water (H2O) is polar because of its bent structure and the electronegativity difference between hydrogen and oxygen.
65. The number of bonding and lone pairs in ClF3 is:
a) 5 bonding pairs and 0 lone pairs
b) 3 bonding pairs and 2 lone pairs
c) 2 bonding pairs and 3 lone pairs
d) 4 bonding pairs and 1 lone pair
Answer: b) 3 bonding pairs and 2 lone pairs
Explanation: In chlorine trifluoride (ClF3), the central chlorine atom has 3 bonding pairs and 2 lone pairs, giving it a T-shaped geometry.
66. Which of the following exhibits tetrahedral geometry?
a) SF6
b) XeF4
c) CH4
d) IF5
Answer: c) CH4
Explanation: Methane (CH4) has tetrahedral geometry with bond angles of 109.5° due to sp3 hybridization of the central carbon atom.
67. The bond order of nitrogen in N2 is:
a) 1
b) 2
c) 3
d) 4
Answer: c) 3
Explanation: Nitrogen (N2) has a bond order of 3, indicating a triple bond between the two nitrogen atoms, which includes one sigma bond and two pi bonds.
68. Which of the following molecules has a dipole moment of zero?
a) HCl
b) CHCl3
c) CO2
d) NH3
Answer: c) CO2
Explanation: Carbon dioxide (CO2) has a linear structure, and the dipole moments of the two polar C=O bonds cancel each other out, resulting in a dipole moment of zero.
69. Which of the following compounds has a trigonal bipyramidal geometry?
a) CH4
b) PCl5
c) SF6
d) XeF4
Answer: b) PCl5
Explanation: Phosphorus pentachloride (PCl5) has a trigonal bipyramidal geometry due to the sp3d hybridization of the central phosphorus atom.
70. Which of the following compounds exhibits octahedral geometry?
a) SF6
b) XeF4
c) IF5
d) PCl5
Answer: a) SF6
Explanation: Sulfur hexafluoride (SF6) has an octahedral geometry with bond angles of 90° due to sp3d2 hybridization.
71. The number of lone pairs on the central atom in SF4 is:
a) 1
b) 2
c) 3
d) 0
Answer: a) 1
Explanation: In sulfur tetrafluoride (SF4), the central sulfur atom has one lone pair and four bonding pairs, resulting in a seesaw shape.
72. Which of the following molecules contains both sigma (σ) and pi (π) bonds?
a) CH4
b) NH3
c) C2H4
d) H2O
Answer: c) C2H4
Explanation: Ethene (C2H4) has a double bond between the two carbon atoms, which consists of one sigma bond and one pi bond. Each carbon also forms sigma bonds with two hydrogen atoms.
73. Which of the following compounds has a pyramidal shape?
a) NH3
b) BF3
c) CH4
d) CO2
Answer: a) NH3
Explanation: Ammonia (NH3) has a trigonal pyramidal shape due to the presence of three bonding pairs and one lone pair on the nitrogen atom.
74. The correct IUPAC name of CH3CH2CH2OH is:
a) 1-propanol
b) 2-propanol
c) 1-butanol
d) ethanol
Answer: a) 1-propanol
Explanation: The compound has three carbon atoms with a hydroxyl group (-OH) attached to the first carbon. Therefore, the correct IUPAC name is 1-propanol.
75. Which of the following molecules has sp2 hybridization at the central atom?
a) CH4
b) C2H4
c) NH3
d) H2O
Answer: b) C2H4
Explanation: In ethene (C2H4), each carbon atom undergoes sp2 hybridization, forming three sigma bonds and one pi bond, resulting in a planar structure.
76. The hybridization of the central atom in PCl5 is:
a) sp
b) sp2
c) sp3
d) sp3d
Answer: d) sp3d
Explanation: Phosphorus in PCl5 is sp3d hybridized, leading to a trigonal bipyramidal structure with bond angles of 90° and 120°.
77. Which of the following compounds has the highest bond angle?
a) CH4
b) NH3
c) H2O
d) CO2
Answer: d) CO2
Explanation: Carbon dioxide (CO2) is a linear molecule with a bond angle of 180°, which is the highest among the given compounds.
78. Which of the following species has an octahedral geometry?
a) SF4
b) PCl5
c) SF6
d) XeF4
Answer: c) SF6
Explanation: Sulfur hexafluoride (SF6) has an octahedral geometry due to sp3d2 hybridization, with bond angles of 90°.
79. Which of the following molecules is nonpolar?
a) NH3
b) H2O
c) CO2
d) CH3Cl
Answer: c) CO2
Explanation: Carbon dioxide (CO2) is nonpolar because it is a linear molecule, and the dipole moments of the polar C=O bonds cancel each other out.
80. The bond angle in ammonia (NH3) is approximately:
a) 90°
b) 104.5°
c) 107°
d) 120°
Answer: c) 107°
Explanation: In ammonia (NH3), the bond angle is approximately 107° due to the lone pair-bond pair repulsion, which slightly reduces the ideal tetrahedral angle of 109.5°.
81. Which of the following species is isoelectronic with CO2?
a) NO2
b) N2O
c) O2
d) H2O
Answer: b) N2O
Explanation: Nitrous oxide (N2O) is isoelectronic with carbon dioxide (CO2) because both have the same number of valence electrons and a similar linear structure.
82. Which of the following molecules has the smallest bond angle?
a) H2O
b) NH3
c) CH4
d) CO2
Answer: a) H2O
Explanation: Water (H2O) has the smallest bond angle of approximately 104.5° due to the repulsion between the two lone pairs on the oxygen atom.
83. The hybridization of carbon in diamond is:
a) sp
b) sp2
c) sp3
d) None of the above
Answer: c) sp3
Explanation: In diamond, each carbon atom is sp3 hybridized, forming four sigma bonds in a tetrahedral structure.
84. The correct IUPAC name for CH3CH2COOCH3 is:
a) Methyl propanoate
b) Ethyl acetate
c) Methyl butanoate
d) Ethyl propanoate
Answer: a) Methyl propanoate
Explanation: The ester has a three-carbon chain derived from propanoic acid (propanoate) and a methyl group (-OCH3). Therefore, the correct IUPAC name is methyl propanoate.
85. Which of the following molecules has a distorted tetrahedral geometry (seesaw)?
a) SF4
b) XeF4
c) IF5
d) CH4
Answer: a) SF4
Explanation: In sulfur tetrafluoride (SF4), the central sulfur atom has four bonding pairs and one lone pair, resulting in a distorted tetrahedral (seesaw) geometry.
86. The bond order of O2 is:
a) 1
b) 2
c) 3
d) 1.5
Answer: b) 2
Explanation: Molecular oxygen (O2) has a bond order of 2, indicating a double bond between the two oxygen atoms.
87. Which of the following compounds contains both ionic and covalent bonds?
a) NaCl
b) H2O
c) NaOH
d) CH4
Answer: c) NaOH
Explanation: Sodium hydroxide (NaOH) contains an ionic bond between Na+ and OH- and a covalent bond within the hydroxyl group (O-H).
88. Which of the following compounds is planar?
a) CH4
b) C2H6
c) C2H4
d) NH3
Answer: c) C2H4
Explanation: Ethene (C2H4) is planar due to sp2 hybridization of the carbon atoms, which results in a flat, trigonal planar structure.
89. The number of sigma and pi bonds in acetylene (C2H2) is:
a) 3 sigma, 2 pi
b) 4 sigma, 1 pi
c) 2 sigma, 2 pi
d) 3 sigma, 1 pi
Answer: a) 3 sigma, 2 pi
Explanation: In acetylene (C2H2), there are 3 sigma bonds (one between the two carbon atoms and two between the carbon atoms and hydrogen atoms) and 2 pi bonds in the carbon-carbon triple bond.
90. Which of the following species is paramagnetic?
a) O2
b) N2
c) F2
d) CO
Answer: a) O2
Explanation: Molecular oxygen (O2) is paramagnetic because it has unpaired electrons in its molecular orbitals, as predicted by molecular orbital theory.
91. The hybridization of carbon in graphite is:
a) sp
b) sp2
c) sp3
d) None of the above
Answer: b) sp2
Explanation: In graphite, each carbon atom is sp2 hybridized, forming three sigma bonds and one pi bond, which results in a planar structure.
92. The bond angle in CH4 is:
a) 90°
b) 104.5°
c) 107°
d) 109.5°
Answer: d) 109.5°
Explanation: Methane (CH4) has a tetrahedral structure with a bond angle of 109.5° due to sp3 hybridization.
93. The correct IUPAC name of CH3COOH is:
a) Methanoic acid
b) Propanoic acid
c) Butanoic acid
d) Ethanoic acid
Answer: d) Ethanoic acid
Explanation: The compound CH3COOH is ethanoic acid, commonly known as acetic acid. It has two carbon atoms in its structure.
94. The shape of the SF6 molecule is:
a) Square planar
b) Trigonal bipyramidal
c) Octahedral
d) Seesaw
Answer: c) Octahedral
Explanation: Sulfur hexafluoride (SF6) has an octahedral shape due to sp3d2 hybridization of sulfur, with bond angles of 90°.
95. Which of the following compounds is aromatic?
a) Cyclohexane
b) Benzene
c) Cyclopropane
d) Ethylene
Answer: b) Benzene
Explanation: Benzene (C6H6) is an aromatic compound because it has a conjugated pi-electron system and follows Huckel’s rule for aromaticity.
96. The bond order of N2 is:
a) 1
b) 2
c) 3
d) 4
Answer: c) 3
Explanation: The nitrogen molecule (N2) has a bond order of 3, meaning there is a triple bond between the two nitrogen atoms.
97. The correct IUPAC name of CH3CH2CH2CHO is:
a) Propanal
b) Butanal
c) Ethanal
d) Propanone
Answer: b) Butanal
Explanation: The compound has four carbon atoms with an aldehyde group (-CHO) at the end, making it butanal.
98. The shape of ClF3 is:
a) Trigonal planar
b) T-shaped
c) Square planar
d) Trigonal bipyramidal
Answer: b) T-shaped
Explanation: Chlorine trifluoride (ClF3) has a T-shaped geometry due to three bonding pairs and two lone pairs on the central chlorine atom.
99. Which of the following species has the same geometry as NH3?
a) H2O
b) CH4
c) PH3
d) BF3
Answer: c) PH3
Explanation: Phosphine (PH3) has a trigonal pyramidal geometry similar to that of ammonia (NH3) due to the presence of one lone pair and three bonding pairs on the central atom.
100. Which of the following has the shortest bond length?
a) HCl
b) HF
c) HI
d) HBr
Answer: b) HF
Explanation: HF has the shortest bond length due to the small size and high electronegativity of fluorine, leading to a stronger and shorter bond compared to other hydrogen halides.
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