Finding the pH of a buffer solution when a strong acid is added

  • Thread starter Thread starter TheSwede
  • Start date Start date
  • Tags Tags
    Acid Buffer Ph
AI Thread Summary
To find the pH of the buffer solution, the pKa of propanoic acid is calculated as 4.85, leading to an initial pH of 4.75 using the Henderson-Hasselbalch equation. When a strong acid like HCl is added, it reacts with the conjugate base, sodium propanate, decreasing its concentration and increasing the concentration of the weak acid, propanoic acid. This shift in concentrations will lower the pH of the buffer solution. The exact new pH after the addition of HCl requires recalculating the concentrations of the acid and base. Understanding these changes is crucial for accurately determining the buffer's new pH.
TheSwede
Messages
1
Reaction score
0

Homework Statement



Three milliliters of a 2.0 M solution of HCL are added to 1 liter of buffer solution containing 0.40 moles of the weak acid, propanoic acid (Ka = 1.4 x 10-5) and .50 moles of its conjugate base, sodium propanate.

1) find the ph of the buffer solution

2) find the ph when the strong acid is added to the buffer solution

Homework Equations



Henderson Hasselbach equation: pH = Pka + log( A- / HA)

The Attempt at a Solution



1) to find the pKa -log(1.4 x 10-5) = 4.85
pH = 4.85 + log(.4/.5) = 4.75
is this correct?

2) clueless
 
Physics news on Phys.org
What happens when you add a strong acid? Is there any reaction taking place? How does it change concentrations of propanate and its conjugate acid?
 

Thread 'Prove that evolution is constant (Provide at least two arguments to support your position)'

I don't get how to argue it. i can prove: evolution is the ability to adapt, whether it's progression or regression from some point of view, so if evolution is not constant then animal generations couldn`t stay alive for a big amount of time because when climate is changing this generations die. but they dont. so evolution is constant. but its not an argument, right? how to fing arguments when i only prove it.. analytically, i guess it called that (this is indirectly related to biology, im...
View full post »

Similar threads

Chemistry Moles of NaOH to Create Buffer Solution pH=6 in 0.42M Ethanoic Acid
Replies
3
Views
3K
Chemistry Solving pH Changes: Adding Acid to a Buffer or Water
Replies
16
Views
3K
Chemistry Understanding how to calculate pH of a buffer solution
Replies
2
Views
1K
Calculating the pH of a Buffer Solution
Replies
7
Views
3K
Chemistry Moles of a conjugate base in a buffer solution
Replies
7
Views
3K
Chemistry Comparing methods of computing pH at equivalence point in titration
Replies
4
Views
1K
Chemistry How to calculate pH at equivalence point using this alternative?
Replies
7
Views
1K
How Does Pre-existing CH3COONa Affect Buffer pH Calculation?
Replies
4
Views
2K
Max Buffering Capacity w/ 0.6 mol HAc & NaOH
Replies
23
Views
3K
Which formula to use to find the pH of a solution?
Replies
20
Views
3K

Hot Threads

Recent Insights

Back
Top