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    Am revising and dont understand how KMnO4 can be used to estimate reducing agents and sodium thiosulphate can be used to estimate oxidising agents.

    Does this mean estimating the strength of the reducing/oxidising agents? Or does it show that they reduce/oxidise things? Am very confused! Also how can you tell how strong the agents are?

    Please help someone! Thanks...x
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    (Original post by BonnieLass)
    Am revising and dont understand how KMnO4 can be used to estimate reducing agents and sodium thiosulphate can be used to estimate oxidising agents.

    Does this mean estimating the strength of the reducing/oxidising agents? Or does it show that they reduce/oxidise things? Am very confused! Also how can you tell how strong the agents are?

    Please help someone! Thanks...x
    what i have been taught is to use K2Cr2O7 for all oxidations - it is slightly weaker oxidising agent than KMnO4 but means you dont have to swap for oxidation of primary alcohol to aldehyde - if you used KMnO4 for this and distilled it, you would still get a c.a. Just use K2Cr2O7 for all oxidations. For reductions i have been taught ethereal LiAlH4: this reduces both c.a.'s, ketones and aldehydes.
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    I think they mean estimate the amounts or concentrations of the agents by their reaction with those compounds.

    Ben
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    its all about titrations

    Titrate the K MnO4 (strong oxidising agent) of known concentration with a reducing agent, and note the vol of KMnO4 used. From this, you can find the concentration of the reducing agent you are testing.
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    (Original post by scarlet ibis)
    its all about titrations
    Isn't everything?!
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    (Original post by allisandro)
    Isn't everything?!
    LOL! Exactly!
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    KMnO4 titrations can be used to standardise a solution of KMnO4, as the solid is rarely pure and the concentration of a solution of it can be found by titrating it with pure iron of a known mass

    *sob* I am so screwed for this exam, I had to teach myself half of it as one of my teachers is totally crap Kc calculations with anything of a greater molar relationship than 1:1 will be the death of me!
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    (Original post by BonnieLass)
    Am revising and dont understand how KMnO4 can be used to estimate reducing agents and sodium thiosulphate can be used to estimate oxidising agents.

    Does this mean estimating the strength of the reducing/oxidising agents? Or does it show that they reduce/oxidise things? Am very confused! Also how can you tell how strong the agents are?

    Please help someone! Thanks...x
    you titrate the reducing agent against a known volume of KMnO4 and find the volume needed to reach end point which is pink! You then use the balanced equation to work back to find conc of reducing agent..

    To find the conc of an oxidising agent, you first add it to (i think excess) KI/H+ and then titrate the now liberated I2 against standard sodium thiosulphate...

    I2 + 2Na2S2O3 --> 2NaI + Na2S4O6

    basically you're trying to find out the concs of the red/ox agents..

    someone correct me if any of this is wrong as i need to know it for tomorrow! heh x
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    maaan i aint gonna get no sleep tonite...
    i no nuffin!
 
 
 

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