Alkynes

Alkynes are unsaturated hydrocarbons with at least one carbon-carbon triple bond. They form homologous series with general formula CnH2n–2. The first stable member of alkyne series is ethyne. It is commonly known as acetylene. The presence of triple bond makes alkynes more reactive than alkanes and alkenes. The major sources of alkynes are natural gas and petroleum. Acetylene can be prepared in the laboratory from calcium carbide. It is a colourless gas with an ether like odour. Acetylene undergoes addition reactions, combustion reaction and ozonolysis reaction. Ethane, ethene and ethyne can be distinguished from one another by the use of different chemical reagents.

To Access the full content, Please Purchase

  • Q1

    The chemical reagent which can be used to distinguish between alkene and alkyne is

    Marks:1
    Answer:

    ammoniacal silver nitrate.

    Explanation:

    When ammoniacal silver nitrate is added to alkynes, white precipitate of silver acetylide is formed whereas there is no such precipitate formation in case of alkenes.

    View Answer
  • Q2

    Acetylene reacts with chlorine in the presence of sunlight to give:

    Marks:1
    Answer:

    Carbon

    Explanation:

    View Answer
  • Q3

    Acetylene is insoluble in:

    Marks:1
    Answer:

    water.

    Explanation:

    Water is an aqueous solvent. Acetylene is organic compound so it will be soluble in organic solvents like alcohol, acetone or chloroform and insoluble in aqueous solvent.

    View Answer
  • Q4

    Marks:1
    Answer:

    Ca(OH)2

    Explanation:

    Ca(OH)2 is formed as by–product when calcium carbide reacts with water.

    View Answer
  • Q5

    The isomerism shown by alkynes is/are

    Marks:1
    Answer:

    chain, position and functional isomerism.

    Explanation:

    Alkynes show position, chain as well as functional isomerism.

    View Answer