Results are out! Find what you need...fast. Get quick advice or join the chat
Hey! Sign in to get help with your study questionsNew here? Join for free to post

chemistry--double indicator titration

Announcements Posted on
    • Thread Starter
    • 0 followers
    Offline

    ReputationRep:
    hello anyone know how to do the attach question and if HCL is added to a solution contain NaOH and Na2CO3. which two will react first and why. please help me .thanks!!
    Attached Thumbnails
    Click image for larger version. 

Name:	qqq.jpg 
Views:	82 
Size:	358.6 KB 
ID:	140143  
    • 4 followers
    Offline

    ReputationRep:
    (Original post by KULER)
    hello anyone know how to do the attach question and if HCL is added to a solution contain NaOH and Na2CO3. which two will react first and why. please help me .thanks!!
    Hi
    In the first titration the following happens:
    NaOH + HCl --> NaCl + H2O
    and
    Na2CO3 + HCl --> NaHCO3 + NaCl


    In the second titration the following happens:
    NaHCO3 + HCl --> NaCl + CO2 + H2O

    So 2nd titre gives moles of NaHCO3
    Which is equal to the moles of Na2CO3

    and then the moles of NaOH = moles of HCl in first titre - moles of Na2CO3

    Then multiply by molar masses and divide by volume used and you have the answers.


    This page shows you the titration curve, which should help you understand why the reactions occur in the order they do. Phenolphthalein changes colour at high pH and methyl orange changes colour at low pH: https://docs.google.com/viewer?a=v&q...UIrHDMgHR6NKQg

Reply

Submit reply

Register

Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. By joining you agree to our Ts and Cs, privacy policy and site rules

  2. Slide to join now Processing…

Updated: April 7, 2012
New on TSR

Single, dating or in a relationship?

Chat about your life and loves in our Relationships forum!

Article updates
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.