November 01, 2024, 12:31:09 AM
Forum Rules: Read This Before Posting


« previous next »
Pages: [1]   Go Down

Topic: titration of vitamin c with starch indicator  (Read 3865 times)

0 Members and 1 Guest are viewing this topic.

Offline futureengineer

  • New Member
  • **
  • Posts: 3
  • Mole Snacks: +0/-0
titration of vitamin c with starch indicator
« on: December 11, 2011, 10:37:07 PM »
 While doing my titration I was adding iodine solution to my vitamin c starch indicator solution and after adding 21 units it turned from clear to yellow. Was this the endpoint?  I thought it was supposed to turn bluish black.
Logged

Offline UG

  • Full Member
  • ****
  • Posts: 822
  • Mole Snacks: +134/-15
  • Gender: Male
Re: titration of vitamin c with starch indicator
« Reply #1 on: December 11, 2011, 10:39:55 PM »
Did you add the starch indicator?
Logged

Offline futureengineer

  • New Member
  • **
  • Posts: 3
  • Mole Snacks: +0/-0
Re: titration of vitamin c with starch indicator
« Reply #2 on: December 12, 2011, 09:34:43 AM »
Yes, At least I think I did.  Could it be that I didn't have enough? I used 20 ml of vitamin c solution and 10 drops of starch indicator.  The starch indicator was made with 1/4 teaspoon starch and 200ml of water.
Logged

Offline UG

  • Full Member
  • ****
  • Posts: 822
  • Mole Snacks: +134/-15
  • Gender: Male
Re: titration of vitamin c with starch indicator
« Reply #3 on: December 12, 2011, 06:06:41 PM »
Wikipedia quotes a standard starch solution is made from 3g of soluble starch in 1 L of heated water, does that sound close to what you did?
Logged

Offline futureengineer

  • New Member
  • **
  • Posts: 3
  • Mole Snacks: +0/-0
Re: titration of vitamin c with starch indicator
« Reply #4 on: December 12, 2011, 10:24:57 PM »
Yes, I used 1 gram per 200 ml of warm water.  That would be 5 grams in a liter wouldn't it?  That should have been plenty of starch.  I wonder if I need to add more than 10 drops into my vitamin c solution.  ???
Logged

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27820
  • Mole Snacks: +1808/-412
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: titration of vitamin c with starch indicator
« Reply #5 on: December 13, 2011, 02:44:20 AM »
http://www.titrations.info/iodometric-titration-Vitamin-C

Procedures I know call for much more starch solution (of a comparable concentration).
Logged
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info
Pages: [1]   Go Up
« previous next »
Sponsored Links