Chemistry

What is the pH of a solution of NaOH 10^-12 M?

  1. 👍 0
  2. 👎 0
  3. 👁 216
  1. how did you find OH? we aren't allowed to use a calculator and the answer book is saying the pH is 7, not 12

    1. 👍 0
    2. 👎 0
  2. I don't want that post to stick around on the web so I'm deleting it. But this response will stay so as to answer your question. I don't know why I answered that way because as I was posting I kept thinking things just weren't right. This ranks up there among the top goofs a chemist can make. The excuse, and excuses don't count, is that I used OH^- = 10^-12 and confused that with K. First question first.
    How did I do the pOH?
    If NaOH is 10^-12, then
    NaOH ==> Na^+ + OH^-
    10^-12..10^-12..10^-12
    So OH^- from NaOH is 10^-12. All of that is good information. Here is where you go from there.
    The water equilibrium is
    .......HOH ==> H^+ + OH^-
    I....liquid....0.....10^-12
    C....liquid....x......x
    E....liquid....x.....x+10^-12

    (H^+)(OH^-) = Kw = 1E-14
    (x)(x+10^-12) = 1E-14
    To avoid a quadratic we assume x + 10^-12 = x and the equation reduces to
    (x)(x) = 1E-14
    x = (H^+) = (OH^-) = sqrt(1E-14) = 1E-7
    and pH = -log(H^+) = -log(1E-7) = 7

    I don't know how my twisted brain got 0.01 out of 10^-12 but the way I arrived at pOH = 2 was -log(0.01) = 2 and you don't need a calculator for that.
    We should always check to make sure our assumption is correct; that is, 10^-12 really is negligible compared with x = (H^+) but 1E-7 + 1E-12 really is, for all practical purposes, 1E-7

    1. 👍 0
    2. 👎 0

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chemistry

    1.) Watch the animation, and observe the titration process using a standard 0.100 M sodium hydroxide solution to titrate 50.0 mL of a 0.100 M hydrochloric acid solution. Identify which of the following statements regarding

  2. chemistry

    A volume of 100mL of 1.00 M HCl solution is titrated with 1.00 M NaOH solution. You added the following quantities of 1.00 M NaOH to the reaction flask. Classify the following conditions based on whether they are before the

  3. Chemistry

    One commercial method used to peel potatoes is to soak them in a solution of NaOH for a short time, remove them from the NaOH, and spray off the peel. The concentration of NaOH is normally in the range of 3 to 6 M. The NaOH is

  4. Chemistry

    Use the dilution relationship (Mi x Vi = Mf x Vf) to calculate the volume of 0.500 M NaOH needed to prepare 500 mL of .250 M NaOH. This is my work ? L Solution = 500mL x (1L/1000mL) = .500L ? mol NaOH = .500 L Solution x (0.250 M

  1. Grade 12 chemistry

    This is the second reaction: HCl(aq)+NaOH(aq)-->NaCl(aq)+H2O(l) (Heat of neutralization) This reaction involves mixing two solutions: 1.00 mol/L NaOH and 1.00 mol/L HCl. Trial 1: 48.0 mL of the NaOH solution is mixed with 47.5 mL

  2. chemistry

    If the endpoint in the titration of KHC8H4O4 solution with the NaOH solution is mistakenly surpassed, will the molar concentration of NaOH solution be reported too high or too low?

  3. chemistry

    three student chemists measured 50.0 mL of 1.00 M NaOH in separate Styrofoam "coffee cup" calorimeters ( Part B). Brett added 50.0 mL of 1.10 M HCI to his solution of NaOH; Dale added 45.5 mL of 1.10 m HCL 9 eqaul moles) to his

  4. ap chem

    A sample of 7.45 grams of NaOH is dissolved into 609 mL of aqueous 0.250 M NaOH (as-sume no volume change). This solution is then poured into 2.18 gallons of water. (You may assume that the two volumes can be added.) What is the

  1. Chemistry

    What is the molality of a glucose solution prepared by dissolving 18.0g of glucose, C6H12O6 in 125g of water? A)0.000794 B)0.144 C)0.699 D)0.794 Molality is the number of moles of solute per kilogram of solvent. Because the

  2. Chemistry

    A sample of 9.4 grams of NaOH is dissolved into 693 mL of aqueous 0.250 M NaOH (assume no volume change). This solution is then poured into 2.37 gallons of water. (You may assume that the two volumes can be added.) What is the

  3. Chemistry

    A sample of 6.41 grams of NaOH is dissolved into 675 mL of aqueous 0.250 M NaOH (assume no volume change). This solution is then poured into 2.28 gallons of water. (You may assume that the two volumes can be added.) What is the

  4. Chem.

    To standardize a solution of NaOH, one uses a primary standard called potassium hydrogen phthalate (KHP). It is a monoprotic acid. It has a molar mass of 204.33g/mol. Suppose you weigh out .556g of KHP and dissolve it in water. It

You can view more similar questions or ask a new question.