1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Solving for pH with diprotic/triprotic acids

  1. Apr 20, 2006 #1


    User Avatar

    i know if you have an acid, say .0001 M HCl, to get the pH you simply take the -log of the acid concentration (which is the same as [H+]), but what if you have a diprotic (H2SO4) or triprotic (H3PO4) acid...do you need to multiply the acid contentration by 2 or 3 to get the new H+ concentration BEFORE plugging it into -log[H+]?

    and the same goes for pOH? eg. Mg(OH)2 needs to be multiplied by 2?
  2. jcsd
  3. Apr 20, 2006 #2


    User Avatar
    Homework Helper
    Gold Member

    Last edited by a moderator: May 2, 2017
  4. Apr 20, 2006 #3
    Mg(OH)2 do not completely ionise in water as do for instance NaOH or KOH.
  5. Apr 20, 2006 #4


    User Avatar

    Staff: Mentor

    Last edited by a moderator: Aug 13, 2013
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Solving for pH with diprotic/triprotic acids
  1. Acids and pH (Replies: 3)

  2. Triprotic Acid (Replies: 2)