Posted by al on Saturday, May 10, 2014 at 7:58pm.
During an acid-base titration, 25 mL of NaOH 0.2 M were required to neutralize 20 mL of HCl.
Calculate the pH of the solution for each:
a) Before titration
b) After adding 24.9 mL of NaOH
c) At equivalence pt
d) After adding 25. 1 mL of NaOH
e) The pH of the equivalence pt during a certain titration is 3.5
f) Which indicator would be adequate for this titration?
g) Which indicator would you suggest to be avoided? Explain
- Chemistry - DrBob222, Saturday, May 10, 2014 at 9:39pm
First, determine the M of the HCl. That will be 25*0.2/20 = 0.25M
Where is the equivalence point. That is at 25.0 mL, NaOH, of course.
The questions divide the titration curve up nicely into
a. at the beginning.
b. before the eq point.
c. at eq pt
d. just after eq pt
It's a matter of keeping account of the mols.
M HCl = 0.2M so pH = -log(HCl)
millimols HCl initially = 5
millimols NaOH added = 4.98
millimols HCl remaining = 5-4.98 = 0.02
M HCl remaining = mmols/mL = 0.02/44.9
pH = -log(HCl)
c. At the eq you have NaCl and H2O. Neither Na^+ nor Cl^- are hydrolyzed; therefore, the pH is 7.0
d. mmols HCl initially = 5.0
mmols NaOH at 25.1 ix 25.1 x 0.2 = 5.02
mmols excess NaOH = 0.02
pH = mmols NaOH/mL solution = 0.02/45.1
I don't understand e.
Look in your text/notes for pH range of indicators.
Answer This Question
More Related Questions
- chemistry - 11.During an acid-base titration, 25 mL of NaOH 0.2 M were required ...
- Chemistry - 1.) Watch the animation, and observe the titration process using a ...
- chemistry - 1. if 15.0mL of 4.5 M NaOH are diluted with water to a volume of ...
- chemistry - I am confused on how to do the last question. Calculate molarity of ...
- please help analytical chemistry - 50 ml of a .1103M solution of formic acid is ...
- chemistry - 50 ml of a .1103M solution of formic acid is titrated with a .2511M ...
- Chemistry - In a acid-base titration, 22.81 mL of an NaOH solution were required...
- chem - Consider the titration of 20 mL of .105M Butric Acid HBut, with .125M ...
- Chem - 1. What is the molarity of a copper(II) dihydroxide [Cu(OH)2] solution if...
- Chemistry - Consider the titration of 20.0mL of 0.300M acetic acid, HAc, with 0....