12th class (fsc) Chemistry unit 9 MCQs
chapter 9 MCQs 12th Class Chemistry
Aromatic Hydrocarbons:
1. Coal tar is the main source of:
a. Non-Aromatic compounds
b. Aromatic compounds
c. Aliphatic compounds
d. None of these
2. Aromatic compounds have:
a. No hydrogen
b. Low hydrogen to carbon ratio in molecular formula
c. High hydrogen to carbon ration
d. None of these
3. Phenanthrene is a fused polycyclic compound contains …… benzene rings:
a. Four
b. Two
c. Five
d. Three
4. Toluene is also called:
a. Hydroxy benzene
b. Amino benzene
c. Methyl benzene
d. Ethyl benzene
5. The m-xylene is also called:
a. 1,3- dimethyl benzene
b. 1,2 dimethyl benzene
c. 1,6-dimethy benzene
d. 1,4-dimethyl benzene
6. The IUPAC name of salicylic acid:
a. 3-amino benzaldeyde
b. 2-amino phenol
c. 2-hydroxy benzonic acid
d. 4-hydroxy benzonic acid
7. Benzene was discovered by:
a. Kekule
b. Hoffman
c. None of them
d. Micheal faraday
8. At room temperature benzene is:
a. Gas
b. Solid
c. Plasma
d. Liquid
9. How many sigma and pi bonds are present in benzene molecule?
a. 12 sigma 6 pi
b. 6 sigma 2 pi
c. 12 sigma 3 pi
d. 9 sigma 3 pi
10. The carbon atom in a benzene ring are:
a. Sp3 hybridized
b. Sp2 hybridized
c. Sp hybridized
d. None of these
11. The structure of benzene is:
a. Square planer
b. Hexagonal
c. Tetrahedral
d. Pyramidal
12. The thre alternate double and sigle bonds in benzene stucture are called:
a. Conjugate bonds
b. Resonating bonds
c. Both a and b
d. None of these
13. In alkanes the C-C bond lenght is:
a. 1.20 A
b. 1.54 A
c. 1.397 A
d. 1.34 A
14. The number of hybridized p-orbitals in benzene ring is:
a. 3
b. 2
c. 1
d. Zero
15. The number of unhybridized p-orbitals in benzene ring is:
a. 6
b. 5
c. 2
d. 3
16. In benzene ring the number of sigma bond , which is formed by sp2 -s overlapping are?
a. 8
b. 4
c. 10
d. 6
17. The C-C bond length in benzene is:
a. Same as in alkanes
b. Greater than those in alkanes
c. Intermediate between those in alkanes and alkenes
d. Shorter than those in alkenes
18. The extra stability of benzene is due to:
a. Ring structures
b. Presence of sigma bond
c. Three double bond
d. Delocalization of pi electrons
19. In which case the C-C bond length is same?
a. 2-butene
b. Propyne
c. Benzene
d. 1-butene
20. The ratio of sigma and pi bonds in benzene is:
a. 4
b. 8
c. 2
d. 6
21. The C-C bonds in benzene is formed by hybridized carbon atom and overlapping is due to:
a. Sp-sp
b. Sp3 -sp3
c. Dsp2 -Dsp2
d. Sp2 -sp2
22. Amongst the following polycyclic compound is:
a. Styrene
b. Xylene
c. Cumene
d. Naphthalene
23. The group that decativates the benzene ring for electrophilec substitution is:
a. Methyl
b. Amino
c. Hydroxy
d. Chlorine
24. The compound that is nitrated with difficulty is:
a. Benzene
b. Toluene
c. Phenol
d. Nitro benzene
25. The xylene which is most easily sulphonated is:
a. Ortho
b. Para
c. Meta
d. All of them