Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    14
    ReputationRep:
    Questions in the title. If a reaction does occur what would you observe? What would observe in a reaction between KI and CuSO4? Any help is appreciated
    • Thread Starter
    Offline

    14
    ReputationRep:
    bump
    • Community Assistant
    • Study Helper
    Offline

    14
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by Nitrogen)
    Questions in the title. If a reaction does occur what would you observe? What would observe in a reaction between KI and CuSO4? Any help is appreciated
    Calcium = Ca (in your title)

    Copper = Cu (in your post)

    Iodide ions react with copper(II) ions, but not calcium ions.

    2Cu2+ + 2I- --> 2Cu+ + I2
    • Thread Starter
    Offline

    14
    ReputationRep:
    (Original post by charco)
    Calcium = Ca (in your title)

    Copper = Cu (in your post)

    Iodide ions react with copper(II) ions, but not calcium ions.

    2Cu2+ + 2I- --> 2Cu+ + I2
    Thank You. When KI reacts with CuSO4 they say a yellow precipitate of sulphur is formed and some say a white/tan ppt of CuI is formed. Are they correct and does that mean you get both ppts?
    • Community Assistant
    • Study Helper
    Offline

    14
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by Nitrogen)
    Thank You. When KI reacts with CuSO4 they say a yellow precipitate of sulphur is formed and some say a white/tan ppt of CuI is formed. Are they correct and does that mean you get both ppts?
    They are not correct ...
    • Thread Starter
    Offline

    14
    ReputationRep:
    (Original post by charco)
    They are not correct ...
    So what ppt is formed?
    Offline

    18
    ReputationRep:
    (Original post by Nitrogen)
    So what ppt is formed?
    I'd guess that it's a displacement reaction where K2SO4 and CuI2 are formed.

    The CuI2 then immediately decomposes to CuI and I2 (unbalanced).
    • Thread Starter
    Offline

    14
    ReputationRep:
    (Original post by thegodofgod)
    I'd guess that it's a displacement reaction where K2SO4 and CuI2 are formed.

    The CuI2 then immediately decomposes to CuI and I2 (unbalanced).
    I guess it is only the white ppt then. thanks!
    • Community Assistant
    • Study Helper
    Offline

    14
    ReputationRep:
    Community Assistant
    Study Helper
    (Original post by thegodofgod)
    I'd guess that it's a displacement reaction where K2SO4 and CuI2 are formed.

    The CuI2 then immediately decomposes to CuI and I2 (unbalanced).
    No, you get a white precipitate of copper(I) sulphate (assuming you start with copper(II) sulphate) and iodine, which imparts an ugly yellowy brown colour to procedings...

    Cu2+ --> Cu2+ + 1e

    2I- + 2e --> I2

    equalise electrons and add:

    2Cu2+ --> 2Cu+ + 2e
    2I- + 2e --> I2
    --------------------------------------------- add
    2Cu2+ + 2I- --> 2Cu+ + I2

    Now put in the spectator ions, assuming copper(II) sulphate:

    2CuSO4 + 2KI --> Cu2SO4 + I2 + K2SO4
 
 
 
  • 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
    Brexit voters: Do you stand by your vote?
  • 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

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