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12th Grade > Chemistry

HYDROCARBONS MCQs

Total Questions : 28 | Page 3 of 3 pages
Question 21.  
 
  1.    H2C = CH-CH=CH2
  2.    CH3-C≡ C-CH3
  3.    CH3-CH2-C≡ CH
  4.    CH3-CH=C=CH2
 Discuss Question
Answer: Option B. -> CH3-C≡ C-CH3
:
B
 
Question 22. An alkene 'X' of the formula C4H8 on ozonolysis produced acetone and formaldehyde. The product obtained when 'X' reacts  with HBr is
  1.    n - butyl bromide
  2.    isobutyl bromide
  3.    sec. butyl bromide
  4.    tert. butyl bromide
 Discuss Question
Answer: Option D. -> tert. butyl bromide
:
D
An Alkene 'X' Of The Formula C4H8 On Ozonolysis Produced Ace...
Question 23.
  1.    1,2 - Benzpyrene
  2.    1,2,5,6 -Dibenanthrecene
  3.    3 - Methyl anthracene
  4.    1,2 -Benzanthracene
 Discuss Question
Answer: Option D. -> 1,2 -Benzanthracene
:
D
You should be able to see that the 3 benzene rings at the bottom form an anthracene.
And using the lowest locant rule, we can assign 1, 2 to the 2 carbons where benzene is attached.
So, the name would be 1,2-benzanthracene
Question 24. Which of the following has maximum boiling point?
 Discuss Question
Answer: Option D. -> 1,2 -Benzanthracene
:
A
The compound without branches will havethe maximum surface area and with the increase in surface area, the boiling point also increases.
The answer should be the linear molecule, n-hexane.
Question 25. PhCCCH3H3O+/Hg+2−−−−−−−A. Then 'A' is 
 Discuss Question
Answer: Option D. -> 1,2 -Benzanthracene
:
A
addition of water followed by tautomerism
Question 26. The polymer used as electrodes in batteries is
  1.    polythene
  2.    polypropene
  3.    polyacetylene
  4.    poly vinyl chloride
 Discuss Question
Answer: Option C. -> polyacetylene
:
C
A solid-state lithium/iodinebatteryhas been formed by directly contacting metallic lithium with iodine-dopedpolyacetylene
Question 27. (CH3)3CHKMnO4−−−−A;CH3(CH2)2CH3HCl−−AlCl3B;CH3(CH2)4CH3Cr2O3,773K−−−−−−1020 atmC;
Correct statements are
A. 'A' remains same                      B. 'B' contains a 30 carbon
C. 'C' follows Huckel's rule            D. Both B and C are aromatic
  1.    A, B, C only
  2.    A, B, C ,D
  3.    A, C, D only
  4.    B, C only
 Discuss Question
Answer: Option A. -> A, B, C only
:
A
A does not undergo any change. There is no strong reason to support KMnO4 attacks a tertiary alkane to give an alcohol
B forms a tertiary alkane through isomerisation
C forms a benzene ring through aromatization reaction
Question 28. CH3CCHNaNH2−−−−XCH2CH2Br−−−−−−Y. Identify the product 'Y' is
  1.    Pent - 2 - ene
  2.    Pent - 2 - yne
  3.    Pent - 1 - yne
  4.    Pentane
 Discuss Question
Answer: Option B. -> Pent - 2 - yne
:
B
X is CH3CCNa+
Y isCH3CCCH2CH3
The first step removes the terminal hydrogen from the given substrate (reactant on the left). Such a removable hydrogen is called an acidic hydrogen. In the next step, the nucleophile - which is rich in electrons - attacks the CBr bond of ethyl bromide. Because of the difference in electronegativity between carbon andbromine, this CBr bond is polar - meaning, the bonding electrons are closer to the more electronegative bromine. This gives rise to the possibility of the carbon of the CBr bond having a slight deficit of electrons; let's just say that this carbon misses electrons and that is where the electron-rich terminal carbon of CH3CC comes in. Hence, the reaction.

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