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!

Solubility in base

  1. Mar 20, 2008 #1
    In my lab, I'm trying to identify an unknown compound. So I did a solubility test of the unknown into 5% NaOH. According to the manual it said that if it appears insoluble,take the supernatant out and add 5% HCl until neutral. If percipitate or turbidity results, it means the unknown is an acid.
    So far I thought this:
    HA (unknown) + OH- <-> H20 + A-
    I'm assuming the conjugate base was in the supernatant, but I'm not sure.
    A- + HCl <-> Cl- + HA
    I'm not sure where the percipitate or turbidity is from. Please help me!
  2. jcsd
  3. Mar 20, 2008 #2


    User Avatar
    Homework Helper
    Education Advisor
    Gold Member

    In the first part, the organic acid present dissolved (why you obtained the very soluble A anion). Later, you added H+ which recombined with the A- giving you back the fairly insoluble organic acid again, the HA. The HA causes this turbidity or precipitation.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Solubility in base
  1. Constant of Solubility (Replies: 1)