Hydrocarbons CBSE Questions & Answers

Hydrocarbons

This is Chemistry Class 11 Hydrocarbons CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
The reaction given below is used to produce polythene. This is an example of _______ reaction
Question 1 figure 1
  • A
    Addition reaction
  • B
    Rearrangement reaction
  • C
    Polymerization reaction
    Correct
  • D
    Substitution reaction
2
The number of position isomers of \({{\text{C}}_{\text{5}}}{{\text{H}}_{\text{8}}}\) is
  • A
    5
  • B
    4
  • C
    3.0
    Correct
  • D
    2
3
Thus ethyne molecule consists of
  • A
    \({\text{one C}}--{\text{C }}\sigma {\text{ bond}},{\text{ two C}}--{\text{H }}\sigma {\text{ bonds and three C}}--{\text{C }}\pi {\text{ bond}}s\)
  • B
    \({\text{one C}}--{\text{C }}\sigma {\text{ bond}},{\text{ three C}}--{\text{H }}\sigma {\text{ bonds and two C}}--{\text{C }}\pi {\text{ bonds}}\)
  • C
    \({\text{one C}}--{\text{C }}\sigma {\text{ bond}},{\text{ two C}}--{\text{H }}\sigma {\text{ bonds and two C}}--{\text{C }}\pi {\text{ bonds}}\)
    Correct
  • D
    \({\text{three C}}--{\text{C }}\sigma {\text{ bond}},{\text{ two C}}--{\text{H }}\sigma {\text{ bonds and three C}}--{\text{C }}\pi {\text{ bonds}}\)
4
In the preparation of alkynes from vicinal dihalides, the reaction is
  • A
    Addition reaction
  • B
    Rearrangement reaction
  • C
    Substitution reaction
  • D
    Elimination reaction
    Correct
5
Majority of the reactions of alkynes are the examples of
  • A
    nucleophilic substitution
  • B
    electrophilic addition
    Correct
  • C
    nucleophilic addition
  • D
    electrophilic substitution
6
When two hydrogen atoms in benzene are replaced by two similar or different monovalent atoms or groups, how many different position isomers are possible?
  • A
    3
    Correct
  • B
    5
  • C
    6
  • D
    2
7
The unusual behavior of benzene is explained by
  • A
    delocalized \(\pi \) electron cloud
    Correct
  • B
    \({\text{s}}{{\text{p}}^{\text{2}}}\) hybridization
  • C
    \({\text{s}}{{\text{p}}^{\text{3}}}\) hybridization
  • D
    kekule structure
8
Aromatics are charachterized by the presence of _____ \(\pi \) electrons in the ring where n is an integer (n = 0, 1, 2, . . .).
  • A
    (4n + 2)
    Correct
  • B
    4n
  • C
    (4n - 2)
  • D
    (4n + 1)
9
Which of the following methods used for production of Benzene?
  • A
    Reduction of phenol
  • B
    Decarboxylation of aromatic acids
  • C
    Cyclic polymerization of ethyne
  • D
    isolation from coal tar
    Correct
10
in Friedel-Crafts alkylation reaction, when benzene is treated with an alkyl halide in the presence of a catalyst, alkylbenene is formed. The catalyst used is
  • A
    anhydrous aluminium chloride
    Correct
  • B
    \({{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}}\)
  • C
    Silver
  • D
    Palladium
11
Some of the polynuclear hydrocarbons having fused benzene ring system have the property of being
  • A
    malleable
  • B
    carcinogenic
    Correct
  • C
    nonflammable
  • D
    conductive
12
Arrange the following in decreasing order of their boiling points. (A) n–butane (B) 2–methylbutane (C) n-pentane (D) 2,2–dimethylpropane
  • A
    A > B > C > D
  • B
    B > C > D > A
  • C
    C > B > D > A
    Correct
  • D
    D > C > B > A
13
Arrange the halogens \({{\text{F}}_{\text{2}}},{\text{ C}}{{\text{l}}_{\text{2}}},{\text{ B}}{{\text{r}}_{\text{2}}},{\text{ }}{{\text{I}}_{\text{2}}},\)in order of their increasing reactivity with alkanes.
  • A
    \({\text{B}}{{\text{r}}_{\text{2}}} < {\text{ C}}{{\text{l}}_{\text{2}}} < {\text{ }}{{\text{F}}_{\text{2}}} < {\text{ }}{{\text{I}}_{\text{2}}}\)
  • B
    \({{\text{F}}_{\text{2}}} < {\text{ C}}{{\text{l}}_{\text{2}}} < {\text{ B}}{{\text{r}}_{\text{2}}} < {\text{ }}{{\text{I}}_{\text{2}}}\)
  • C
    \({{\text{I}}_{\text{2}}} < {\text{ B}}{{\text{r}}_{\text{2}}} < {\text{ C}}{{\text{l}}_{\text{2}}} < {\text{ }}{{\text{F}}_{\text{2}}}\)
    Correct
  • D
    \({\text{B}}{{\text{r}}_{\text{2}}} < {\text{ }}{{\text{I}}_{\text{2}}} < {\text{ C}}{{\text{l}}_{\text{2}}} < {\text{ }}{{\text{F}}_{\text{2}}}\)
14
The increasing order of reduction of alkyl halides with zinc and dilute HCl is
  • A
    R–I < R–Br < R–Cl
  • B
    R–Cl < R–Br < R–I
    Correct
  • C
    R–Br < R–I < R–Cl
  • D
    R–Cl < R–I < R–Br
15
The correct IUPAC name of the following alkane is
Question 15 figure 1
  • A
    3,6 – Diethyl – 2 – methyloctane
    Correct
  • B
    3 – Ethyl – 5 – isopropyloctane
  • C
    3 – Isopropyl – 6 – ethyloctane
  • D
    5 – Isopropyl – 3 – ethyloctane