Turn on thread page Beta
    • Thread Starter
    Offline

    1
    ReputationRep:
    I do Edexcel Chemistry. A couple of questions...

    1) What colour is the manganate (VII) ion and what colour does it turn when reduced (to Mn2+)

    2) When you titrate sodium thiosulphate with iodine (aq) you need to add starch solution close to the end point. How do you know when you are getting close to the end point?!

    Thanks in advance
    Offline

    13
    (Original post by KP Nuts)
    I do Edexcel Chemistry. A couple of questions...

    1) What colour is the manganate (VII) ion and what colour does it turn when reduced (to Mn2+)

    2) When you titrate sodium thiosulphate with iodine (aq) you need to add starch solution close to the end point. How do you know when you are getting close to the end point?!

    Thanks in advance
    1) pink
    2)you are getting a faint yellow colour of iodine?
    Offline

    2
    ReputationRep:
    (Original post by KP Nuts)
    I do Edexcel Chemistry. A couple of questions...

    1) What colour is the manganate (VII) ion and what colour does it turn when reduced (to Mn2+)

    2) When you titrate sodium thiosulphate with iodine (aq) you need to add starch solution close to the end point. How do you know when you are getting close to the end point?!

    Thanks in advance
    1) purple to pink

    2) when you are near the end-point, a faint yellow colour is apparent in the titre. Then you add a couple of drops of starch solution, which turns the colour from pale yellow to blue/black (this colour shows that iodine is still present in solution). Then you continue to titrate until to blue/black colour changes to colourless

    hope it helps
    Offline

    13
    (Original post by rainjan_4now)
    1) purple to pink

    2) when you are near the end-point, a faint yellow colour is apparent in the titre. Then you add a couple of drops of starch solution, which turns the colour from pale yellow to blue/black (this colour shows that iodine is still present in solution). Then you continue to titrate until to blue/black colour changes to colourless

    hope it helps
    ..
    • Thread Starter
    Offline

    1
    ReputationRep:
    Thanks a lot!
 
 
 
Turn on thread page Beta
Updated: June 17, 2005
The home of Results and Clearing

1,182

people online now

1,567,000

students helped last year

University open days

  1. SAE Institute
    Animation, Audio, Film, Games, Music, Business, Web Further education
    Thu, 16 Aug '18
  2. Bournemouth University
    Clearing Open Day Undergraduate
    Fri, 17 Aug '18
  3. University of Bolton
    Undergraduate Open Day Undergraduate
    Fri, 17 Aug '18
Poll
Do you want your parents to be with you when you collect your A-level results?

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.