12th Class Chemistry Mcqs With Answers Chapter 9| 2nd Year chemistry mcqs with answers pdf

written by Assad Javaid | August 10, 2021
12 class chemistry mcqs 2021
12th Class Chemistry Mcqs With Answers Chapter 1 12th Class Chemistry Mcqs With Answers Chapter 2
12th Class Chemistry Mcqs With Answers Chapter 3 12th Class Chemistry Mcqs With Answers Chapter 4
12th Class Chemistry Mcqs With Answers Chapter 5 12th Class Chemistry Mcqs With Answers Chapter 6
12th Class Chemistry Mcqs With Answers Chapter 7 12th Class Chemistry Mcqs With Answers Chapter 8
12th Class Chemistry Mcqs With Answers Chapter 9 12th Class Chemistry Mcqs With Answers Chapter 10
12th Class Chemistry Mcqs With Answers Chapter 11 12th Class Chemistry Mcqs With Answers Chapter 12
12th Class Chemistry Mcqs With Answers Chapter 13 12th Class Chemistry Mcqs With Answers Chapter 14
12th Class Chemistry Mcqs With Answers Chapter 15 12th Class Chemistry Mcqs With Answers Chapter 16
12th Class Chemistry Mcqs With Answers Chapter 17 12th Class Chemistry Mcqs With Answers Chapter 18
12th Class Chemistry Mcqs With Answers Chapter 19 12th Class Chemistry Mcqs With Answers Chapter 20
12th Class Chemistry Mcqs With Answers Chapter 1


Chapter No 9

Hydrocarbons

1. Which of the following acid can be used as a catalyst in Friedel Crafts  reaction choose which one is correct:

  1. AlCl3
  2. HNO3
  3. BeCl2
  4. NaCl

2. During nitration of benzene, the active nitrating agent is choose which one is correct:

  1. NO3
  2. NO+2
  3. NO−2
  4. HNO3

3. The electrophile in aromatic sulphonation is choose which one is correct:

  1. H2SO4
  2. HSO−4
  3. SO+3
  4. SO3

4. Hydrogen to carbon ratio in aromatic hydrocarbons is choose which one is correct:

  1. Low
  2. High
  3. Equal
  4. None

5. The second substitution in benzene ring would give rise isomeric products choose which one is correct:

  1. One
  2. Two
  3. Three
  4. Four

6. Molecular mass of benzene is determined by choose which one is correct:

  1. Vapour density method
  2. X-ray diffraction
  3. Elemental analysis
  4. Degradation method

7. C − H bond lengths in benzene are choose which one is correct:

  1. 0.99 Å
  2. 1.09 Å
  3. 1.12 Å
  4. 1.397 Å

8. Each carbon in benzene ring is ⎯⎯⎯⎯ hybridized choose which one is correct:

  1. sp
  2. sp2
  3. Sp3
  4. None of these

9. On hydrogenation benzene liberates energy choose which one is correct:

  1. 358.5 kJ/mole
  2. 119 kJ-mol−1
  3. 208 kJ-mol−1
  4. 150.5 kJ-mol−1

10. The benzene ring is oxidized to maleic anhydride when strongly heated with choose which one is correct:

  1. Ni/200°C
  2. V2O5/450°C
  3. AlCl3/150°C
  4. Sunlight

11. Main source of aromatic compound is choose which one is correct:

  1. Petroleum
  2. Coal-tar
  3. Living organism
  4. Dead marine animals

12. When acetylene is heated at 300°C in Cu-tube, the product obtained is choose which one is correct:

  1. Benzene
  2. Thiophene
  3. Divinyl acetylene
  4. Xylene

13. Which one of the following species is ortho and para director choose which one is correct:

  1. CHO
  2. −SO3H
  3. −NO2
  4. Cl

14. The carbon-carbon bond distance in benzene choose which one is correct:

  1. 1.54°A
  2. 1.34°A
  3. 1.2°A
  4. 1.39°A

15. In toluene synthesis by Friedel Craft, the reactants in addition to anhydrous  AlCl3 are choose which one is correct:

  1. C6H6 + CH4
  2. C6H5Cl
  3. C6H6 + CH3Cl
  4. C6H5Cl + CH4

16. Benzophenone is also known as choose which one is correct:

  1. Biphenyl
  2. Dimethyl Ketone
  3. Diphenyl Ketone
  4. Methylphenyl Ketone

17. The no. of possible isomers of xylene are choose which one is correct:

  1. 2
  2. 3
  3. 4
  4. 5

18. The molecular formula of naphthalene is choose which one is correct:

  1. C10H8
  2. C10H10
  3. C10H12
  4. C12H12

19. Chlorine react with benzene in the presence of sunlight to give choose which one is correct:

  1. Chlorobenzene
  2. Benzoyl chloride
  3. Ortho-para dichlorobenzene
  4. Hexachlorobenzene

20. Effect of substituent on benzene ring is due to choose which one is correct:

  1. Resonance
  2. Inductive effect
  3. Both A.  and (b)
  4. Unpredictable

21. In which of the following cases, the benzene rings are isolated choose which one is correct:

  1. Naphthalene
  2. Phenanthrene
  3. Anthracene
  4. Triphenylmethane

22. Benzene is stable than ethene because it has choose which one is correct:

  1. More π-bonds
  2. Localized π-electrons
  3. Delocalized π-electrons
  4. More σ-bonds

23. Which of the following is ortho and para directing group choose which one is correct:

  1. −OH
  2. −OCH3
  3. −CHO
  4. −NH2

24. Among the following compounds which can be readily sulphonated choose which one is correct:

  1. Phenol
  2. Benzene
  3. Nitrobenzene
  4. Chlorobenzene

25. Structure of benzene is resonance hybrid of all ⎯⎯⎯⎯ structures choose which one is correct:

  1. 3
  2. 4
  3. 5
  4. 6

26. Aromatic hydrocarbons are derivatives of choose which one is correct:

  1. Paraffins
  2. Alkene
  3. Benzene
  4. Cyclohexane

27. Which of the following explains the structure of benzene choose which one is correct:

  1. Atomic orbital treatment of benzene
  2. Resonance method
  3. Both A.  and (b)
  4. None

28. The conversion of n-hexane into benzene by heating in the presence of  (Al2O3 + SiO2 + Cr2O3) is called choose which one is correct:

  1. Isomerization
  2. Aromatization
  3. Dealkylation
  4. Rearrangement

29. Toluene can be converted to benzoic acid in the presence of choose which one is correct:

  1. dil. NaOH
  2. dil. HNO3
  3. Conc. HNO3
  4. Acidified KMnO4

30. Cyclic structure of benzene was proposed by choose which one is correct:

  1. Dewar
  2. Faraday
  3. Down
  4. Kekule

31. Benzene does not undergo choose which one is correct:

  1. Addition
  2. Substitution
  3. Polymerization
  4. Aromatization

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