III. Compound theory questions
Compound questions
There are a total of 41 compound questions, which are important content-oriented in the summary part of this chapter. Click the ‘Answer’ button to see the corresponding answers and explanations, and click the ‘Go back’ button to slove the next questions.
1. Which of the following is an example of a polyatomic anion?
A. PO43– : Phosphorous
B. ClO– : Hypochlorate
C. BrO3– : Bromate
D. BrO4– : Bromine tetraoxide
E. SO42– : Sulfite
2. Which of the following acids is INCORRECTLY named?
A. HCl : Hydrochloric acid
B. HNO2 : Nitrous acid
C. HNO3 : Nitric acid
D. HClO4 : Perchloric acid
E. H2SO3 : Sulfuric acid
3. Which of the following compounds is INCORRECTLY named?
A. CaCl2 : Calcium chloride
B. Ba3(PO4)2 : Barium phosphate
C. SnF4 : Tin(IV) fluoride
D. P2O5 : Diphosphorus pentoxide
E. CuCrO4 : Copper(IV) chromate
4. Which of the following compounds is correctly named?
A. PCl3 : Phosphorus chloride
B. SO42– : Sulfite ion
C. HCN : Hydrocyanic acid
D. Ca(ClO)2 : Calcium(II) hE. pochloride
E. SeO2 : Selenium(II) oxide
5. Which of the following is the correct chemical formula for magnesium carbonate?
A. MgCO
B. MgCO3
C. Mg2CO3
D. Mg(CO3)2
E. Mg2(CO3)2
6. What type of bonding is in the compound CaCl2?
A. Covalent bonding
B. Ionic bonding
C. Hydrogen bonding
D. Metallic bonding
E. B and D
7. Which of the following molecules would be expected to have the highest lattice energy?
A. AlCl3
B. MgCl2
C. KI
D. MgBr2
E. KBr
8. Choose the correct statement(s) for ionic bonds.
A. II only
B. I and III
C. II and IV
D. II, IV, and V
E. I, III, and V
9. Choose the correct statement(s) for covalent bonds.
1. II only
2. I and III
3. II and IV
4. II, IV, and V
5. I, III, and V
10. Choose the INCORRECT statement for metallic bonds.
A. Attraction force by delocalized electrons.
B. High conduction of heat and electricity.
C. High melting and boiling point.
D. Easily brittle in the solid state.
E. Chemical bonds between single metallic atoms.
14. Choose an INCORRECT statement about the two bonds between H-F and H-Cl.
A. H-F bond has bigger difference of electronegativity than H-Cl.
B. H-F bond has higher polarity than H-Cl.
C. H-F bond has a higher boiling point than H-Cl.
D. H-F bond has a higher melting point than H-Cl.
E. All are correct.
15. Which of the following is the most important factor in determining the polar covalent bonded or non-polar covalent bonded molecules?
A. Electronegativity
B. Valence electrons
C. Electro affinity
D. Ionization energy
E. Molecular weight
16. Which of the following substances is the most easily soluble in the water at the same temperature and pressure?
A. BF3
B. NH3
C. CH4
D. CO2
E. BeF2
17. Which of the following is a non-polar molecular compound?
A. CH4
B. Cl2
C. PH3
D. CHCl3
E. A and B
18. Which of the following is the correct statement?
A. To make a strong hydrogen bond, hydrogen must combine with atoms that have a strong electronegativity and smaller atomic radius.
B. London dispersion force is a stronger bond than dipole-dipole force when the molecules have a similar molecular weight.
C. Halogen and noble gases usually both have London dispersion and dipole-dipole forces.
D. The strength order of the boiling and melting point from lower to higher is HI < HBr < HCl.
E. Molecules that have covalent bonds have a higher polarity than molecules that have ionic bonds.
19. Which of the following molecules has the highest boiling point?
A. CH4
B. SiH4
C. GeH4
D. SnH4
E. PbH4
23. All of the following molecules could have hydrogen bonds EXCEPT ____________________ .
A. NH3
B. NF3
C. H2O
D. HF
E. None of the above
24. Which of the following has the hydrogen bond between the molecules?
A. H3CH2CH3
B. CH3CH2F
C. N(CH3)3
D. CH3Cl
E. CH3CH2OH
27. Which of the following has the same lone pairs of electrons at the central atoms?
A. CH2O and HO2
B. H2Se and PCl3
C. NH3 and
D. BH3 and ClF3
E. BH4– and CH3–
28. Which compound follows the octet rule on the central atom?
A. BCl3
B. BeBr2
C. SbCl52-
D. NH4+
E. XeF4
30. In the molecule PCl3, the atom P has __________ lone pair(s) and __________ bond(s). Also, the total number of valence electrons in the molecule is __________.
A. 0, 2, 20
B. 1, 3, 20
C. 1, 2, 24
D. 1, 3, 26
E. 2, 3, 26
31. According to VSEPR theory, what is the shape of XeOF4 molecule?
A. Square planar
B. Linear
C. Trigonal planar
D. Square Planar
E. Square pyramidal
32. Which of the following has the most similar shape to AsCl3 by VSEPR theory?
A. NH4+
B. PF5
C. ClF3
D. CCl3–
E. AlH3
33. According to VSEPR theory, which of these molecules has a shape that is different from the others?
A. H2O
B. SO2
C. CS2
D. Br2O
E. H2Te
34. Which of the following is an INCORRECT statement?
A. H-O-H bond angle in H2O is 109.5o.
B. O-C-O bond angle in CO2 is 180o.
C. F-B-F bond angle in BF3 is 120o.
D. Cl-S-Cl bond angle in SCl6 is 90o.
E. H-Si-H bond angle in SiH4 is 109.5o.
35. Which of the following molecules has sp3 hybridization on the central atom?
A. ClF3
B. KrF2
C. PCl3
D. BeCl2
E. AlCl3
38. Which of the following is NOT related to paramagnetism?
A. Unpaired electrons
B. Positive susceptibility
C. Weaker than ferromagnetism
D. Short terms of magnets
E. Fe, Co, and Ni
41. Two crystal lattice structures have one atom and four atoms per unit cell. These structures are called _______________ and _______________.
A. Simple cubic, face-centered cubic
B. Body-centered cubic, face-centered cubic
C. Face-centered cubic, simple cubic
D. Body-centered cubic, simple cubic
E. Simple cubic, body-centered cubic
Answers
3. E
CrO42– is a double charged anion. Cu2+ + CrO42– → Cu2(CrO4)2 → CuCrO4. Therefore, CuCrO4 is Copper(II) chromate.
4. C
PCl3 : Phosphorus trichloride.
SO42– : Sulfate ion.
Ca(ClO)2 : Calcium hypochloride.
SeO2 : Selenium dioxide.
6. B
Attraction of opposite charges between the metal atom (Ca2+) and the nonmetal atom (Cl–) is called ionic bond.
7. A
Lattice energy is the force required to break ionic bonds. The smaller size of metal and nonmetal atoms, the greater lattice energy.
8. E
Ionic bonds are held together by transferring an electron between metal and nonmetal elements such as NaCl or LiF. They have usually higher polarity and solve easily in polar solvents.
9. C
Covalent bonds are formed by sharing electrons between their nonmetal elements such as Cl2 or CH4. These bonds have a weaker polarity than ionic bonds.
10. D
Except for D, all these statements are true of metallic bonds. Ionic bonds, not metallic bonds, are easily brittle in the solid state.
13. A
The bigger difference in electronegativity between two atoms, the higher polarity. The C-F bond has the biggest difference of electronegativity among them.
14. E
All are correct statements. H-F has a hydrogen bond, so this bond has a higher melting and boiling point than H-Cl even though H-Cl has a higher molecular weight than H-F.
15. A
The polarity of molecules is decided by the difference in electronegativity between two atoms.
16. B
NH3 and H2O are polar molecular compounds. The polar molecules are easily soluble in polar solvent and the non-polar molecules are easily soluble in non-polar solvent. Therefore, NH3 can easily solve in H2O.
17. E
PH3 and CHCl3 are polar molecular compounds because the sum of the vector of polarities is not zero. In a non-polar molecular compound, the sum of the dipole moments is zero.
18. A
Dipole-dipole force is a stronger bond than London dispersion force when the molecules have a similar molecular weight. Halogen gases (F2, Cl2) and noble gases (Ne, Ar) have only London dispersion force because they are non-polar molecules. The strength order of the boiling and melting point from lower to higher is HCl < HBr < HI because the boiling and melting point of molecules usually depend on London dispersion force (molecular size or weight) rather than dipole-dipole force. Molecules that have ionic bonds have a higher polarity than the molecules that have covalent bonds.
19. E
The molecular boiling point is affected by the molecular size between non-polar molecules (London dispersion force). A greater molecular size corresponds to a higher boiling point. Pb is the biggest element on the list.
20. E
Coordinate covalent bonds happen when one molecular having non-pair electrons accepts two lone-pair electrons. BF3 and H+, which have non-pair electrons, accept two lone-pair electrons each from NH3 and H2O, and then become stable coordinate covalent molecules. This follows the octet rule.
21. C
London dispersion forces happen by the short-lived polarizability from electron motions between two neighboring polar or non-polar molecules. Strength and melting and boiling points are directly proportional to the size of molecules.
22. C
The order of strength between molecules: London dispersion force < dipole-dipole force < hydrogen bond. The molecular force of I is London dispersion force, which is between non-polar molecules. II is a hydrogen bond., III is dipole-dipole force, which is between polar molecules.
24. E
A, B, C, and D cannot have hydrogen bonds. Hydrogen bonded molecules have the interaction force between molecules of O-H, N-H, and F-H.
25. C
Molecular structures with more resonances have greater stabilization such as O3, OCN–, or NO3–.
26. E
Stable molecules usually follow the octet rule. E cannot be a molecule formed by the octet rule.
27. C
NH3 and have the 1 lone pair at their central atoms.
0 lone pair: CH2O, BH3, BH4–
1 lone pair: PCl3, NH3, IF4+, CH3–
2 lone pairs: H2O, H2Se, ClF3
28. D
Atoms that could be the exception to the octet rule are Be, B, Al, Sb, Xe, and so forth (see fig. 3).
29. C
B, D, and E do not follow the octet rule. Therefore, A and C could be the stable resonance structures. C is a more stable structure than A because of the negative charge on the oxygen, which has more electronegativity than nitrogen.
32. D
The shape of AsCl3 is trigonal pyramidal.
NH4+: Tetrahedral
PF5: Trigonal bipyramidal
ClF3: T-shaped
CCl3–: Trigonal pyramidal
AlH3: Trigonal planar
Therefore, answer is D
34. A
H-O-H bond angle in H2O is less than 109.5o because the electrons in two lone pairs repel each other.
35. C
ClF3: 3 bonds and 2 lone pairs (3+2) = sp3d (1+3+1)
KrF2: 2 bonds and 3 lone pairs (2+3) = sp3d (1+3+1)
PCl3: 3 bonds and 1 lone pair (3+1) = sp3 (1+3)
BeCl2: 2 bonds and 0 lone pair (2+0) = sp (1+1)
AlCl3: 3 bonds and 0 lone pair (3+0) = sp2 (1+2)
37. B
Formal charge
= Number of valence electrons – bonding number – number of non-binding electrons
= 5 – 2- 4
= -1
38. E
Paramagnetism is the positive attractive force to magnetic field by unpaired electrons. This magnetism is weak and short term. Li, Na, Mg, Al, Ca, and O2 are examples of paramagnetism. Fe, Co, and Ni are examples of ferromagnetism.
39. A
Paramagnetism: Li, Na, Mg, Al, Ca, O2
Ferromagnetism: Fe, Co, Ni
Diamagnetism: Cu, Ag, Au, N2, F2
40. B
A body-centered cubic unit cell, which is one centered atom with 1/8 of each corner atom, has total two atoms.