Qualification > Sciences

chemistry question

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cashem'up:

--- Quote from: perrychan527 on May 05, 2010, 05:51:37 pm ---i got some of ur pt. What did u mean is that the extra drop of MnO4- is purple itself, but when it goes to a large amount of colourless solution, solution become pink?

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yea see if it becomes purple then it goes way off the end point as there is too much excess however when only one drop excess added there will be a faint permanent pink color that wont go even if u shake it, yes as u said a purple drop in large colorless soln will be pink.......

XaM!!:

--- Quote from: ima_shah2002 on May 05, 2010, 07:04:29 pm ---yea see if it becomes purple then it goes way off the end point as there is too much excess however when only one drop excess added there will be a faint permanent pink color that wont go even if u shake it, yes as u said a purple drop in large colorless soln will be pink.......

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ya agreed... when ur titrating at some point sol becomes v.light yellow, that is v.near to end point... it means that a single drop could be in excess... like half of a drop is needed to complete reaction so a full drop makes the colour pure pinkish which is not required vvlight pink is the endpoint...


 n nid indicator isnt used in back titration...

cashem'up:

--- Quote from: nid404 on May 05, 2010, 05:47:43 pm ---Paper?

any particular indicator mentioned?

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yea actualy pretty much wen kmno4 is being reduced in a reaction the color change itself is the indicator so u dont really need an indicator

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