SDN members see fewer ads and full resolution images. Join our non-profit community!

Qs on KBB P942 #5. Plz.

Discussion in 'DAT Discussions' started by ddsjc2014, Jun 13, 2008.

  1. ddsjc2014

    ddsjc2014 7+ Year Member

    Oct 22, 2007
    on P942 #5 why the mole of NaCl is 0.5 Mole.
    I don't get it. someone please explain this with little detail.
    Thanks guys.

    Question. If 10mL of 1M NaOH is titrated with 1 M HCl to a pH of 2, what volume of HCl was added?
    Last edited: Jun 13, 2008
  2. SDN Members don't see this ad. About the ads.
  3. Danny289

    Danny289 Member 2+ Year Member

    Dec 2, 2006
    for your second question answer is 10.20 mL?
  4. TeamGuo

    TeamGuo 2+ Year Member

    Apr 1, 2008
    this question indicates that you are titrating a strong base with strong acid which means when you react 2 things that are both strong they react in 1:1 fashion.

    So if you have 10 mL of NaOH, you can throw in 10 mL of HCl to get to neutral pH. The acid and base will cancel each other since they are both strong.

    So here once you throw in 10 mL of HCl to neutralize the sol'n you have 20 mL total volume at pH = 7. Now you want to know how much more of HCl do I need to add to get to pH = 2.

    1M HCl x X mL = 0.01 M x (20 + X) mL

    X = additional HCl being added.
    0.01 M = from the pH value of 2.

    So X = 0.2 mL, now you just add to the 10 mL ending with 10.2 mL of HCl.

Share This Page