Hydrocarbons, Functional Groups and Polymers

Attempt the quiz above first, then review every question with its correct answer and a short explanation below.

1. Q1.The simplest hydrocarbon is:

   • A.methane✓ Correct Answer
   • B.ethane
   • C.ethene
   • D.benzene

   Explanation: Its formula is CH4.

2. Q2.The main constituent of natural gas and biogas is:

   • A.butane
   • B.methane✓ Correct Answer
   • C.hydrogen
   • D.propane

   Explanation: CNG is mainly methane.

3. Q3.Carbon shows a valency of:

   • A.two
   • B.four✓ Correct Answer
   • C.three
   • D.six

   Explanation: It forms four covalent bonds.

4. Q4.The functional group of alcohols is:

   • A.-COOH
   • B.-CHO
   • C.-OH✓ Correct Answer
   • D.-NH2

   Explanation: Ethanol is C2H5OH.

5. Q5.Diamond and graphite are:

   • A.allotropes of carbon✓ Correct Answer
   • B.isotopes of carbon
   • C.compounds of carbon
   • D.isobars of carbon

   Explanation: They differ in the arrangement of carbon atoms.

6. Q6.LPG mainly consists of:

   • A.methane only
   • B.carbon monoxide
   • C.hydrogen only
   • D.butane and propane✓ Correct Answer

   Explanation: It is stored as a liquid under pressure.

7. Q7.The general formula of alkanes is:

   • A.CnH2n
   • B.CnH2n+2✓ Correct Answer
   • C.CnH2n-2
   • D.CnHn

   Explanation: Alkanes are saturated hydrocarbons.

8. Q8.The general formula of alkenes is:

   • A.CnH2n+2
   • B.CnH2n-2
   • C.CnH2n✓ Correct Answer
   • D.CnH2n+1

   Explanation: They contain a carbon-carbon double bond.

9. Q9.The general formula of alkynes is:

   • A.CnH2n-2✓ Correct Answer
   • B.CnH2n+2
   • C.CnH2n
   • D.CnH2n+1

   Explanation: They contain a carbon-carbon triple bond.

10. Q10.The gas used in welding along with oxygen is:

    • A.methane
    • B.ethane
    • C.propane
    • D.ethyne (acetylene)✓ Correct Answer

    Explanation: The oxy-acetylene flame is very hot.

11. Q11.The molecular formula of benzene is:

    • A.C6H12
    • B.C6H14
    • C.C6H6✓ Correct Answer
    • D.C5H6

    Explanation: It is a ring-shaped aromatic hydrocarbon.

12. Q12.Saponification is the reaction of a fat or oil with an alkali to form:

    • A.alcohol and acid
    • B.polymer and water
    • C.ester and gas
    • D.soap and glycerol✓ Correct Answer

    Explanation: Sodium hydroxide gives sodium soaps.

13. Q13.Polythene is a polymer of:

    • A.methane
    • B.benzene
    • C.propane
    • D.ethene✓ Correct Answer

    Explanation: Many ethene units join through addition polymerisation.

14. Q14.Isomers are compounds with the same:

    • A.structure but different formulas
    • B.colour but different mass
    • C.molecular formula but different structures✓ Correct Answer
    • D.name but different atoms

    Explanation: Butane and isobutane are examples.

15. Q15.Formic acid, which causes pain in ant stings, is also called:

    • A.methanoic acid✓ Correct Answer
    • B.ethanoic acid
    • C.propanoic acid
    • D.lactic acid

    Explanation: Ethanoic acid is acetic acid.

16. Q16.The property of carbon atoms to link with each other in long chains is called:

    • A.allotropy
    • B.isomerism
    • C.sublimation
    • D.catenation✓ Correct Answer

    Explanation: It explains the vast number of carbon compounds.

17. Q17.Urea, the first organic compound made from an inorganic source, was synthesised by:

    • A.Antoine Lavoisier
    • B.Joseph Priestley
    • C.Friedrich Wöhler✓ Correct Answer
    • D.Marie Curie

    Explanation: In 1828 he overturned the vital force theory.

18. Q18.The monomer of PVC is:

    • A.ethene
    • B.vinyl chloride✓ Correct Answer
    • C.tetrafluoroethene
    • D.styrene

    Explanation: Polyvinyl chloride is used in pipes and cables.

19. Q19.Teflon is a polymer of:

    • A.vinyl chloride
    • B.tetrafluoroethene✓ Correct Answer
    • C.ethene
    • D.propene

    Explanation: It is used for non-stick coatings.

20. Q20.The functional group -COOH is characteristic of:

    • A.carboxylic acids✓ Correct Answer
    • B.alcohols
    • C.aldehydes
    • D.ketones

    Explanation: Acetic acid is CH3COOH.