Download Different Chemical Bond in and more Exercises Organic Chemistry in PDF only on Docsity!
Organic Chemistry Questions
The Covalent Bond
- The hybridization of the central carbon in CH 3 C≡N and the bond angle CCN are
a. sp^2 , 180°. b. sp , 180°. c. sp^2 , 120°. d. sp^3 , 109°.
- Which of the following statements about an sp hybridized carbon is FALSE?
a. It is divalent. b. It forms bonds that are linear. c. It has two p orbitals. d. It always forms triple bonds to carbon.
- Which molecule has the largest dipole moment?
a. HCl b. CCl (^4) c. H 2 S d. CO 2
- What are the hybridizations of carbons 1 and 2 respectively in the following structure?
a. sp^3 and sp^2 b. sp^2 and sp^3 c. sp^3 and sp d. sp^2 and sp^2
- What are the hybridizations of atoms 1 and 2 respectively in the following structure?
a. sp^3 and sp^2 b. sp^2 and sp^3 c. sp^3 and sp d. sp^2 and sp^2
- Identify the orbital hybridization at the two indicated carbons in the molecule below.
a. C^1 : sp ; C^2 : sp b. C^1 : sp^2 ; C^2 : sp^2 c. C^1 : sp ; C^2 : sp^2 d. C^1 : sp^2 ; C^2 : sp
- How many total resonance structures can be drawn for the following anion (include those without separation of charge)?
a. 1 b. 2 c. 3 d. 4
- What is the specific rotation 20[α ]D of the following molecule?
a. +4.42 o b. +0.442 o c. +44.2 o d. – 44.2o
- Which of the following physical properties differ for each of a pair of enantiomers?
a. solubility in ethanol b. direction of rotation of plane-polarized light c. boiling point and melting point d. index of refraction
- Determine the double bond stereochemistry ( E or Z ) for the following molecules.
a. A : E ; B : E b. A : Z ; B : Z c. A : E ; B : Z d. A : Z ; B : E
- Determine the double bond stereochemistry ( E or Z ) for the following molecules.
a. A : E ; B : E b. A : Z ; B : Z c. A : E ; B : Z d. A : Z ; B : E
Molecular Structure and Spectra
- A strong signal at 1700 cm–1^ in an IR spectrum indicates the presence of a(n)
a. alcohol b. ether c. carbonyl d. amine
- A strong signal at 3400 cm–1^ in an IR spectrum indicates the presence of a(n)
a. alcohol b. ether c. carbonyl d. amine
- Deduce the structure of an unknown compound with molecular formula C 9 H 10 O using information given by its infrared spectrum.
Intensity (peak): Frequency (cm–1^ ): s 3100 m 2900 m 2800 s 1710 m-w 1600 m-w 1475 m 1465 m 1450 m 1375
a.
b.
c.
d.
- Deduce the structure of an unknown compound with molecular formula C 5 H 8 O using information given by its infrared spectrum.
Intensity (peak): Frequency (cm–1^ ): m 3100 m 2800 s 1705 m-w 1640 m 1450 m 1375
a.
b.
c.
d.
- Which of the following compounds a–d has an IR absorption at 3300 cm–1^?
a. a b. b c. c d. d
- Deduce the structure of an unknown compound using the following 1 H NMR spectrum, mass spectroscopy data, and IR spectrum.
(^1) H NMR spectrum:
δ1.30 (triplet, 6H) δ4.29 (quartet, 4H) δ 7.4–7.9 (multiplet, 4H)
Mass Spectrum: m/e: Intensity: (as % of base peak) 222 10% 177 38% 149 100%
IR Spectrum: Intensity (peak): Frequency (cm–1^ ): s 3100 m 2900 m 2800 s 1740 m-w 1600 m-w 1475 m 1465 m 1450 m 1375 s 1300–
a.
b.
c.
d.
- A compound of formula C 5 H 12 gives 1 signal in the 1 H NMR and 2 signals in the 13 C NMR. The compound is
a. pentane. b. 2-methylbutane. c. 2,2-dimethylpropane. d. Cannot tell without more information.
- How many methyl peaks would you expect to observe in the 1 H NMR spectrum of cis -1,4-dimethylcyclohexane?
a. 1 b. 2 c. 3 d. 4
- The 1 H NMR spectrum of a compound is shown below. What is the structure of the compound?
a.
b.
c.
d.
- How many absorption bands will appear in the 13 C NMR spectrum for the following compound?
a. 4 b. 6 c. 7 d. 8
- How many absorption bands will appear in the 13 C NMR spectrum for the following compound?
a. 5 b. 7 c. 8 d. 9
- Not only the molecular ion peak, but all peaks in the mass spectrum of chlorobenzene are accompanied by a smaller peak one mass unit higher. This peak is due to which of the following?
a. capture of an H atom b. presence of a 13 C c. presence of a 36 Cl d. capture of a proton
- What is the exact mass (in atomic mass units: C, 12.0000; H, 1.0078; N, 14.0031; O, 15.9949) of the molecular ion of a compound with molecular formula C 3 H 8 O?
a. 60. b. 60. c. 60. d. 59.
- Which of the following cyclohexane conformations has the MOST energy (is the LEAST stable)?
a. chair b. half-chair c. boat d. twist-boat
- Which of the following molecules is trans -1, 2-dimethylcyclohexane?
a.
b.
c.
d.
- What is the IUPAC name of the following molecule?
a. 1,2-dimethylhexane b. 2,4-dimethylcyclohexane c. Dimethylcyclohexane d. 1,3-dimethylcyclohexane
- Which compound has the highest melting point?
a. decane b. 2,2,3,3-tetramethylbutane c. 2,2,3-trimethylpentane d. 4-methylnonane
- Which of the following alkanes will have the lowest boiling point?
a.
b.
c.
d.
- Which of the following cycloalkanes has the MOST strain energy?
a. cyclobutane b. cyclopentane c. cyclohexane d. cycloheptane
- The balanced equation for the combustion of pentane is
a. 4 C 5 H 12 + 2 O 2 → 20 CH 4 + 4 H 2 O b. 2 C 3 H 8 + O 2? → CH 4 + 2 H 2 O c. C 5 H 12 + 8 O 2 → 5 CO 2 + 6 H 2 O d. C 3 H 8 + 5 O 2 → 3 CO 2 + 4 H 2 O
- What is the major product of the following reaction?
a.
b.
c.
d.
- What is the major product of the following reaction?
a.
b.
c.
d.
- Which of the following occurs during the initiation stage of a radical mechanism?
a. Nonradicals are formed from radicals. b. Radicals are formed from other radicals. c. Radicals are formed from nonradicals. d. Nonradicals are formed from other nonradicals.
