12th class (Fsc) Chemistry unit 8 MCQs
51. In alkynes as bonds between carbon atoms are:
a. One is sigma and two are pi bond
b. All sigma bond
c. One is pi and two are sigma bond
d. All pi bond
52. The removal of HX from a molecule is called:
a. Dehydration
b. Hydrogenation
c. Hydroxylation
d. None of these
53. Identify the hydrocarbon formed when vicinal dihalide reacts with strong base:
a. Ethene
b. Methane
c. Ethyne
d. Ethane
54. Identify the hydrocarbons formed when tetrahalides react with Zn or Mg:
a. Ethene
b. Methane
c. Ethyne
d. Ethane
55. When an aqueous solution of Na or K salt of unsaturated dicrboxylic acid is subjected to electrolysis alkyne is formed. The method is known as:
a. Kolbe’s electrolytic method
b. Sabatier sender’s reaction
c. None of these
d. Bow’s process
56. Acetylene has characteristics ethereal smell resembling that of:
a. Carlic
b. Ginger
c. Onion
d. Vinegar
57. Which of the following compound in hydrolysis give acetylene?
a. Al4C3
b. CaC2
c. Cu2Cl2
d. Mg2C3
58. The monomer of neoprene is:
a. Chloroprene
b. Isoprene
c. 1.3- butadiene
d. Acrylonitrile
59. When acetylene is passed through a copper tube at 300oC it polymerizes to:
a. Benzene
b. Polyacetylene
c. Cyclohexane
d. Polyethylene
60. Polyvinyl chloride is prepared by the reaction of HCL with:
a. Benzene
b. Acetylen
c. Methane
d. Ethane
61. The thermal hydrogen atom of alkyne is:
a. Amphoteric
b. Acidic
c. Basic
d. None of these
62. Sodium acetylide is:
a. Coordinate
b. Ionic in nature
c. Covalent in nature
d. None of these
63. When a compound X is shaken with ammoniacal cuprous chloride, a red precipitate is formed compound X is possibly:
a. Olefin
b. Acetylene
c. Benzene
d. Parafin
64. A compound X is formed while a white precipitate with ammonical solution of silver nitrate, what should be the compound X:
a. Ethene
b. Methane
c. Ethyne
d. Ethane
65. Acetylene is used in the manufacturer of:
a. Ethyl alcohol
b. Rubber
c. Plastic
d. All of these
66. Which gas is used for welding purpose?
a. Nitrogen
b. Acetylene
c. Methane
d. Butane
67. Compounds having pi bonds are in general:
a. More reactive
b. Less reactive
c. Non reactive
d. Both a and b
68. Which bond is weaker?
a. coordinate
b. Pi bond
c. Sigma bond
d. None of these
69. Addition of X2 to an alkyne yields:
a. Trihalide
b. Dihalide
c. Formaldehyde
d. Tetrahalide
70. The higher reactivity of an alkene as compare to alkane is due to:
a. Hydrogen bond
b. Pi bond
c. Sigma bond
d. None of these
71. Identify the compound when acetylene combine with H2O in the presence of 10% H2SO4 and HgSO4 as catalyst:
a. Acetaldehyed
b. Carbinol
c. Glyco
d. Methanol
72. Identify the compound which is formed by hydration of propyne:
a. Propyl alcohol
b. Acetaldehyed
c. Formadehde
d. Ketone
73. Addition of NH to ethyne yields:
a. Ethyl nitrile
b. Acrylonitrile
c. Fromaldehyde
d. Methyl nitrile
74. The geometry of acetylene is:
a. Trigonal
b. Angular
c. Linear
d. Bent
75. Number of acidic hydrogen present in 2-butyne:
a. 3
b. 1
c. 2
d. None