Chemistry Chapter 10 Entry Test MCQs
76. Which one of the following conversions involve change in hybridization?
a. H2O → H3O+
b. NH3 → NH4+
c. BF3 → BF4–
d. CH4 → C2H6
77. The number of lone pairs on Xe in XeF2 , XeF4 and XeF6 , respectively are
a. 1, 2, 3.
b. 3, 2, 1.
c. 6, 4, 2.
d. 2, 4, 6.
78. Pairs of species having identical shapes for molecules is:
a. CF4 , SF4
b. BF3 , PCl3
c. XeF2 , CO2
d. PF5 , IF5
79. Which one of the following pairs of molecules will have permanent dipole moments for both members?
a. NO2 and O3
b. SiF4 and NO2
c. SiF4 and CO2
d. NO2 and CO2
80. Among the following compounds, the one that is polar and has the central atom with sp2 hybridization is:
a. HClO2
b. SiF4
c. H2CO3
d. BF3
81. The correct order regarding the electronegativity of hybrid orbitals of carbon is
a. sp < sp2 < sp3
b. sp < sp2 > sp3
c. sp > sp2 > sp3
d. sp > sp2 < sp3
82. Pick the incorrect statement:
a. Greater s-character, shorter bond
b. Greater bond order, shorter the bond
c. Greater electronegativity difference, shorter the bond.
d. Greater lone pairs on bonded atoms, shorter bond
83. The compounds ethyne, ethene and ethane contain, respectively, C≡C, C=C and C–C bonds. What is the expected sequence of carbon–carbon bond lengths and bond enthalpies?
a. Bond lengths: C≡C > C=C > C–C; bond enthalpies: C≡C < C=C < C–C.
b. Bond lengths: C≡C < C=C < C–C; bond enthalpies: C≡C < C=C < C–C.
c. Bond lengths: C≡C > C=C > C–C; bond enthalpies: C≡C > C=C > C–C.
d. Bond lengths: C≡C < C=C < C–C; bond enthalpies: C≡C > C=C > C–C.
84. When the H-N-H bond angles in the species NH2–, NH3 and NH4+ are arranged in order of increasing bond angle (smallest bond angle first), which order is correct?
a. NH3 < NH2– < NH4+
b. NH2– < NH3 < NH4+
c. NH2– < NH4+ < NH3
d. NH4+ < NH3 < NH2–
85. The dipole moments of methane and its halogen derivatives are in the order
a. CH3Cl < CH2Cl2 < CHCl3 < CH4
b. CH4 < CH2Cl2 < CHCl3 < CH3Cl
c. CH4 < CH3 Cl < CH2Cl2 > CHCl3
d. CH4 < CHCl3< CH2Cl2 < CH3Cl
86. Which one of the following will possess highest (N-N) bond length?
a. N2O4
b. N2O
c. N2
d. N2H4
87. O-O bond length is minimum in
a. O2+
b. O2–
c. O22-
d. O2