Hey there! Sign in to join this conversationNew here? Join for free

Chemistry primary, secondary and tertiary alcohols & halogenalkane making, testing. Watch

    • Thread Starter
    Offline

    0
    ReputationRep:
    A few question guys =)
    1. How would you make aldheyde from a primary alcohol, and not make a carboxylic acids instead.
    2. How would make a carboxylic acid from primary alcohol.
    3. what is the difference in making a aldheyde and carboxylic acid from a primary alcohol.
    4. How can you test for an aldeyhide, carboxylic acid and a ketone.

    I know that you can use sliver nitrate to test for halogenalkanes, but how do test to see if they are primary, secondary or tertiary halogenalkanes.

    thanks in advance =)
    • PS Reviewer
    Offline

    20
    ReputationRep:
    PS Reviewer
    (Original post by Hi, How are you ?)
    A few question guys =)
    1. How would you make aldheyde from a primary alcohol, and not make a carboxylic acids instead.
    2. How would make a carboxylic acid from primary alcohol.
    3. what is the difference in making a aldheyde and carboxylic acid from a primary alcohol.
    4. How can you test for an aldeyhide, carboxylic acid and a ketone.

    I know that you can use sliver nitrate to test for halogenalkanes, but how do test to see if they are primary, secondary or tertiary halogenalkanes.

    thanks in advance =)

    1) An aldehyde is made by heating under distillation . You react the primary alcohol with the oxidising agent (potassium dichromate with sulphuric acid). Collect product in a beaker.

    2) Basically the same as above, however you are using a reflux condenser as opposed to a distillation apparatus. Heat of course.

    3) Difference? Your heating under distillation when obtaining the aldehyde, however you are heating under reflux when obtaining the carboxylic acid.

    Test for aldehyde: Add fehlings solution. A brick red precipitate indicates an aldehyde is present.

    Test for ketone: run the same test as above, however no reaction will occur as the fehlings solution does not react with the ketone (more specifically, doesn't react with the C=O bond), hence the solution remains blue. (which is the colour of the fehlings solution)
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by James A)
    1) An aldehyde is made by heating under distillation . You react the primary alcohol with the oxidising agent (potassium dichromate with sulphuric acid). Collect product in a beaker.

    2) Basically the same as above, however you are using a reflux condenser as opposed to a distillation apparatus. Heat of course.

    3) Difference? Your heating under distillation when obtaining the aldehyde, however you are heating under reflux when obtaining the carboxylic acid.

    Test for aldehyde: Add fehlings solution. A brick red precipitate indicates an aldehyde is present.

    Test for ketone: run the same test as above, however no reaction will occur as the fehlings solution does not react with the ketone (more specifically, doesn't react with the C=O bond), hence the solution remains blue. (which is the colour of the fehlings solution)
    Hi, thanks
    Could you say that for the carboxylic acids, you could use concentarted H2SO2 and K2Cr2O7 aswell and heat for a longer time?

    What about the last question about primary, secondary and tertiary halogenalkanes?
    • PS Reviewer
    Offline

    20
    ReputationRep:
    PS Reviewer
    (Original post by Hi, How are you ?)
    Hi, thanks
    Could you say that for the carboxylic acids, you could use concentarted H2SO2 and K2Cr2O7 aswell and heat for a longer time?

    What about the last question about primary, secondary and tertiary halogenalkanes?
    Well yeah, you are heating for a longer time, because you want the reaction to go to completion.

    When you want the aldehyde, your not going to completion with the reaction, because it's only 'partial oxidation'.


    I'm not sure about the last one :/
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    What's your favourite Christmas sweets?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Quick reply
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.