1. Not finding help here? Sign up for a free 30min 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!

Acid concentration Q's

  1. Jun 14, 2004 #1


    User Avatar

    Having some problems with the following question:

    Trimethylacetic acid [tex]C_4 H_{11} COOH[/tex]is a weak monoprotic acid. When 0.0010 mol of Trimethylacetic acid was dissolved in 100mL of water, the concentration of trimethylacetic ion was found to be [tex]3.0 \times 10^{ - 4} mol.L^{ - 1} [/tex]

    a) What is monoprotic acid?
    An Acid that donates only one proton.

    b) Use the above data to work out [tex]pK_a [/tex] for Trimethylacetic acid.
    now pKa = -log[Ka] think? How would I go about working Ka out?

    c) What volume of 0.2M KOH would be required to neutralise this solution of trimethylacetic acid?
    For this I would just work out how many moles are in the 100mL solution, and then use that to work out how how much volume of KOH I would need to add.
    However I'm unsure how to work out how many mols are in the 100mL solution, It's an easy units conversion problem im sure, but I suck at it :(
  2. jcsd
  3. Jun 14, 2004 #2
    Look at the concentration of the ion.

    If there's that much in the solution that exists as an ion, an equal amount must exist as H+.
  4. Jun 14, 2004 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    [tex]Ka= \frac {[H^+][A^-]} {[HA]}[/tex]


    [tex] [H^+] = 10^{-7} + [A^-][/tex]
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?