Posted by millie on Wednesday, October 7, 2009 at 9:20pm.
a buffer composed of 0.50mol acetic acid and 0.50mol sodium acetate is diluted to a volume of 1.0L. The pH of the buffer is 4.74. How many moles of NaOH must be added to the buffer solution to increase its pH to 5.74?
chemistry - DrBob222, Wednesday, October 7, 2009 at 9:48pm
I assume you are using pKa = 4.74 so that
pH = 4.74 + log 0.5/0.5 =
= 4.74 + log 1 = 4.74 + 0 = 4.74.
If we call acetic acid HAc and the acetate ion (the base) Ac, then
To make the pH 5.74 we calculate the B/A as follows:
5.74 = 4.74 + log B/A
You can go through the calculation but you should end up with (Ac)/(HAc) = 10
Then we write the equation
HAc + NaOH = NaAc + H2O
HAc = 0.5 to start
Ac = 0.5 to start.
We add x moles NaOH.
The HAc after the reaction will be 0.5 - x and the Ac will be 0.5+x
Just plug those values into the
(Ac)/(HAc) = 10 and solve for x.
I always like to put that value in and resolve the equation to see if I get 5.74.
Post your work if you get stuck.
chemistry - millie, Wednesday, October 7, 2009 at 10:07pm
thanks for your help, it worked out :)
Answer This Question
More Related Questions
- school - What is the pH of 0.1 M formic acid solution? Ka=1.7„e10-4? What is the...
- chemistry - If you add 5.0 mL of 0.50 M NaOH solution to 20.0 mL to Buffer C, ...
- chemistry - 1L of a buffer composed of acetic acid and sodium acetate has a pH ...
- Chemistry - Assume you have prepared 100.0 mL of a buffer solution using 0.400 ...
- Food Chemistry - Calculate the amounts and pH values for preparing the following...
- CHEMISTRY HELP! - a. According to the Henderson-Hasselbalch equation, how many ...
- Chemistry - If you need to prepare 250.0 mL of a pH 5.00 buffer that has a total...
- college chem - a. According to the Henderson-Hasselbalch equation, how many ...
- chemistry - What is the pH of a buffer solution if you have 250 ml of a 1.56M ...
- Biochemistry - A buffer solution is prepared by mixing 2.50 mL of 2.00M sodium ...