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Find the molarity and ph of diluted HCl

  1. Nov 19, 2008 #1
    1. The problem statement, all variables and given/known data
    To 25.000 mL of distilled water in a 50 mL beaker, you add exactly 19 drops of 0.100 M HCl and swirl to mix. If exactly 20 drops of HCl are required to make 1.000 mL

    2. Relevant equations
    Calculate molarity of the diluted HCl and pH of the diluted HCl

    3. The attempt at a solution
    i really don't know where to start.
    i'd really appreciate the help i can get
  2. jcsd
  3. Nov 19, 2008 #2


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    What is the final volume of the solution? How many moles of HCl are in 19/20 mL of 0.100 M HCl? What is the definition of molarity and how can you calculate pH if you know the molarity of the acid?
  4. Nov 19, 2008 #3
    19/20 ml of HCL? you mean the drops
    what about .025L or .001L isn't that the vol. for HCl
    all i know is molarity is moles/volume
    i'm still lost. since there's two volumes given and no moles to do the molarity equation
  5. Nov 19, 2008 #4


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    If you add 50 mL to 1 mL how many mL is the final solution? Now do that for 25 mL plus 19/20 mL.... That's final volume.

    Know how to calculate molarity? It's not moles/volume, btw.
  6. Nov 19, 2008 #5


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    Molarity means moles of substance of interest per liter of solution.

    Use your given information to calculate moles of HCl added;
    The volume of resulting solution is the sum of the volume of the individual volumes of everything added to make the solution. You want "Moles of HCl per liter of solution".

    Note that for pH question, you want to know what pH means; and know that your HCl is essentially completely ionized in aqueous solution.
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