posted by .

Hi,may I have your help?
I have posted a titration question that I'm trying to solve. The correct answer to the problem is 0.128 M, however,I have arrived at the answer: 0.000128 M. Here's the question:

If 38.30 mL of 0.250 M NaOH is used to titrate 25.0 mL of phosphoric acid,what is the molarity of the acid? The balanced equation is

H3PO4(aq)+3 NaOH(aq)--- Na3PO4(aq)+3H2O (l).

Here's how I've tried to solve for the answer:
38.3 mL solution * (0.250 mol NaOH/1000 mL)(1 mol H3PO4/3 mol NaOH)= 3.19 moles H3PO4

(3.19 mol H3PO4/25.0 mL solution)(1L\1000 mL)= 1.276*10^-4
=0.000128 M

I appreciate your help.

  • Chemistry -

    0.0128 M is correct.
    Thanks for showing your work.
    Your error is in the first line. Instead of 3.19 moles, you never divided by the 1000 mL in the second term, and it should be 0.00319 moles. Then 0.00319 moles/0.025L = 0.12767 = 0.128 M.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Algebra I

    Question:The number of students on the football team is two more than three times the number of students on the basketball team. If the basketball team has Y students, write a variable expression for the number of students on the football …

    Please answer my question that I posted at 6:10 quickly because I have to in a little while!!! Your answer is posted. However, you're still going to have to do the math to find the equivalencies. If you'd like to post your answers, …
  3. Algebra

    The answer in the book however says -(5x^2-17x-9)/(x-3)(x+2) so I don't know what I am doing wrong, can you take me step by step through the problem. I have a lot of problems, but I think once I understand what I am doing wrong with …
  4. Literature

    Hi, I just have a question about a confusing question to me in a poem that I have to answer... The poem is Annabel Lee. Here's the question they are asking: What was the effect of the repeated rhymes?
  5. Math

    I posted these 2 questions a couple of days ago and although the help I received would have been more appreciated if it didn't come with an underhanded comment, I did see where I made my mistake with the first question, however I would …
  6. Statistics

    On a very short quiz, there is one multiple choice question with 5 possible choices (a, b, c, d, e) and one true or false question. Assume you are taking the quiz but do not have any idea what the correct answer is to either question. …
  7. calculus

    I have posted this question earlier and had the answer given to me this way. But my teacher needs to know what type of factorization I used and I have tried to figure it out but have NO clue!! This is the question. Solve the following …
  8. physics

    A mass m is gently placed on the end of a freely hanging spring. The mass then falls 21.3 cm before it stops and begins to rise. What is the frequency of the oscillation?
  9. Algebra

    In a science competition with ten problems, a student gets 5 points for a correct answer and loses 2 points for an incorrect answer. If Alice answered every problem and her score was 29, how many correct answers did she have?
  10. Math

    How to solve this problem? Here is what I have done so far. question --> 12(1/2)% x (1/2)/(3/4) First i solved the fractions (1/2) x (4/3) =4/6 I changed the 12(1/2)% into a decimal by solving 1/2, which is .5 which equals to 12.5

More Similar Questions