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Description of benzen

Which of the following is an INCORRECT description of benzene?
a. The CCC bond angles are all equal to 120 o
b. The 6-membered ring contains alternating double and single carbon-carbon bonds
c. The molecule may be drawn as resonance hybrid of 2 Kekule structures
d. The molecule is planar

Which of the following criteria is NOT used to determine if a molecule is aromatic?
a. Structure is cyclic
b.Each carbon atom in the ring has sp3 hybridization
c.Structure is planar or nearly so
d.The pi network contains 4N +2 electrons

Which of the following numbers of pi electrons would not lead to aromaticity?
a. 2
b. 6
c. 8
d. 10

The compound cyclobutadiene would be best catagorized as
a. anti-aromatic
b. non-aromatic
c. aromatic
d. none of the above

Which of the following is also an acceptable name for 3-nitrophenol?
a. o-nitrophenol
b. m-nitrophenol
c. p-nitrophenol
d. none of the above

Solution This solution is FREE courtesy of BrainMass!

Which of the following is an INCORRECT description of benzene?
B is the answer. In reality this type of structure (alternating double and single carbon-carbon bonds) does not exist. The correct structure must be drawn as a ring inside the hexagon to represent benzene.
References:
http://www.chemguide.co.uk/basicorg/bonding/benzene1.html
http://chemistry2.csudh.edu/rpendarvis/BenzStr.html

Which of the following criteria is NOT used to determine if a molecule is aromatic?
B is the answer. An aromatic hydrocarbon is a cyclic compound where all the atoms in the ring(s) are sp2 and having a free "p" orbital. All the other options are true for aromatic compounds.
References:
http://members.aol.com/logan20/aromatic.html

Which of the following numbers of pi electrons would not lead to aromaticity?
This test the Huckel rule 4n + 2. In the recommended reference we can see that:
n 4n + 2 Pi electrons
0 4(0) + 2 = 2
1 4(1) + 2 = 6
2 4(2) + 2 = 10
3 4(3) + 2 = 14
4 4(4) + 2 = 18
So C (number 8) must be the answer. Eight numbers of pi electrons would not lead to aromaticity
Reference:
http://members.aol.com/logan20/aromatic.html

The compound cyclobutadiene would be best catagorized as anti-aromatic. A is the answer.
Reference:
http://www.chem.ucalgary.ca/courses/351/Carey5th/Ch11/ch11-7-1.html

Which of the following is also an acceptable name for 3-nitrophenol?
Because the NO2 and OH groups are positioned in 1 and 3 positions (OH-postion1; NO2 position 3). This means we have C as the answer because this is the para position.
Reference:
http://dl.clackamas.cc.or.us/ch106-02/nomencla3.htm