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Chemistry-Bleach Q's

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  • 30-05-2008 11:34am
    #1
    nisey89
    Closed Accounts Posts: 13 ✭


    Hi could someone help me answer these questions i found on bleach please because im unsure of the answer.

    HCL is an unsuitable acid for this titration.Why? What acid is usually used?

    Why is it necessary for the potassium iodide to be in excess??

    Why is the sulfuric acid diluted?

    Name a substance which can provide the iodine ions that are needed. What would be the result of not using such a substance?

    if any body has any more strange/hard/q's they are unsure of please reply.
    and the same goes for iron tablet exp.:):)


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    #2
    kaki
    Registered Users Posts: 674 ✭✭✭kaki


    Shouldn't use HCl, as it might cause chlorine gas to be given off when it comes into contact with the bleach, use H2SO4 instead.


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    #3
    dip
    Closed Accounts Posts: 105 ✭✭dip


    HCL is an unsuitable acid for this titration.Why? What acid is usually used?
    It'll react with the hypochlorite in the bleach to liberate chlorine gas.

    Why is it necessary for the potassium iodide to be in excess??
    The iodide ions must be in excess so that ALL the hypochlorite ions can react to form Iodine.
    => The number of iodine molecules formed = The number of hypochlorite ions present.

    Potassium Iodide acts to keep the Iodine in soultion.
    (I2 + KI -><- KI3) = unstable
    ^ reversable reaction
    (I3)- is much more soluble than I2 and it is as the (I3)- that the iodine is kept in solution.


    Name a substance which can provide the iodine ions that are needed. What would be the result of not using such a substance?
    Potassium Iodide


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