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Buffer Solutions

  1. Nov 29, 2004 #1
    I am very stuck on this question and I am hoping someone can help me with this. We did this in lab and mine did not come out right, but I still have to turn it in and my lab teacher said to figure it out!
    Buffer solutions using a cabbage dye indicator:
    Which of these is a buffered solution after the addition of 5 drops of HCl, 10 drops HCl:
    distilled water (I think no?)
    0.1 M NaCl
    pH 12 buffer
    pH 2 buffer

    Which if these is a buffered solution after 5 drops NaOH, 10 drops NaOH:
    juice(pH around 4.5)
    soda(pH around 3)
    pH 12 buffer
    pH 2 buffer

    I know this is a loaded question, but I can't figure out which ones...HELP!!!
  2. jcsd
  3. Nov 29, 2004 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    Hi pinky, a buffer is a solution that contains a mixture of acids and bases.. if an acid or base is added to the solution the pH won't change. If you add a solution to a buffer outside it's buffering range, the buffer will loose it's power.

    So thinking of that, which do you think the correct answer will be to your own question? Hint: what is the approximate pH of HCl and NaOH?
  4. Nov 29, 2004 #3
    HCl is a pH 2 and NaOH is about pH-13-14 right? So, pH 2 is a buffer solution when HCl is added and not when NaOH is right? The rest I am still lost on!?
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