A hydrocarbon is an organic compound in organic chemistry that is made entirely of hydrogen and carbon. The majority of hydrocarbons are colourless and hydrophobic, and their odours are typically insignificant or best characterised by those of gasoline and lighter fluid. They can be found in a wide variety of molecular forms, including gases (like methane and propane), liquids (like hexane and benzene), low-melting solids (like paraffin wax and naphthalene), and polymers (such as polyethene and polystyrene).
Download Class 11 Chemistry Worksheet on Chapter 13 Hydrocarbons – Set 5 PDF.
CBSE Class 11 Chemistry Chapter 13 Hydrocarbons – Set 5
Q-1: Aromatic substances emit a sooty flame because
a) They contain rings of carbon atoms.
b) They contain a sizable amount of carbon.
c) They contain a sizable amount of hydrogen.
d) They don’t react with airborne oxygen.
Q-2: The order of appearance of the following with rising temperature during the refining of the crude oil is
a) Diesel, Kerosene oil, Gasoline
b) Kerosene oil, Gasoline, Diesel
c) Gasoline, Diesel, Kerosene oil
d) Gasoline, Kerosene oil, Diesel
Q-3: Which of the following has the least hindrance to rotation around the carbon-carbon bond?
a) C2H4
b) C2H6
c) C2Br6
d) C2H2
Q-4: 1-Bromopentane on reaction with alcoholic potash gives
a) 1-Pentene
b) 1-Pentanol
c) 2-Pentanol
d) 2-Pentene
Q-5: Hexadecane is a petroleum term that is frequently referred to as
a) Octane
b) Cetane
c) Petrol
d) LPG
Q-6: Give the structures of the compounds which on reductive ozonolysis give:
i) Propane-1,3-dial
ii) Acetaldehyde, formaldehyde and carbon dioxide
Q-7: What effect does the branching of an alkane have on its melting point?
Q-8: Which fuel has the highest octane rating among 2, 2, 3-trimethylbutane, 2, 2, 4-trimethylpentane, and 2, 2, 3, 3-tetramethylbutane? Explain.
Q-9: What is solvent naphtha? What purpose does it serve?
Q-10: How will you prove benzene double bonds differ somewhat from olefin double bonds?
Q-11: Why propane has only one eclipsed conformation while butane has two? Explain.
Q-12: How will you distinguish between buta-1,3-diene and but-1-yne?
Q-13: Which substances make up LPG primarily?.
Q-14: What are primary and secondary suffixes as applied to IUPAC nomenclature?
Q-15: Analyse 2-methylpropane (isobutane). Along the C1-C2 bond, sighting:
i) Create Newmann projections for the conformations that are the most and the least stable.
ii) Calculate the energy difference between these conformations if interactions between hydrogen and hydrogen cost 4.18 kJ/mol and interactions between hydrogen and methyl cost 5.85 kJ/mol.
Q-16: Why do C-C bonds rather than C-H bonds break during the cracking of alkanes?
Q-17: Which of the following polymerises most readily?
a) Ethyne
b) Ethene
c) Buta-1,3-diene
Q-18: a) Why is cyclopropane very reactive as compared to cyclohexane?
b) How will you separate propene from propyne?
c) Name the chain isomer of C5H12, which has a tertiary hydrogen atom.
Q-19: Give the structure of an alkene (C4H8), which, when treated with H2O/H2SO4, gives C4H10O, which cannot be resolved into optical isomers.
Q-20: Treatment of hydrocarbon (A) C6H10 with H2/Ni, H2/ Lindlar’s catalyst and Na/NH3 (l) results in the formation of three distinct reduction products (B), (C), and (D), respectively. Heating (A) with NaNH2 in an inert solvent result in the formation of the salt (E), but heating (A) with an ammoniacal AgNO3 solution does not. In a subsequent reaction with CH3I, compound (E) transforms into (F). N-butyric acid was produced along with other products when compound (D) underwent oxidative ozonolysis. Give proper reasons and structures ranging from A to F.
Download the access answers to the Chemistry Worksheet for Class 11 Chemistry Chapter 13 Hydrocarbons Set – 5.
