PH of HCl solution as a function of volume.

In summary, for a 1L 2M HCl solution with complete ionization, the current pH is -log(2). To find the pH of a new dilute solution with V litres of water added, the concentration of the solution would need to be recalculated in terms of V and then the negative log of that concentration can be found. Consider the autoionization of water when doing this calculation.
  • #1
Bipolarity
776
2

Homework Statement


You have a 1L of a 2M HCl solution. Assume that the HCl completely ionizes.
a) Calculate the pH of the solution right now.
b) You now add V litres of water to the solution.
Find the pH of the new dilute solution in terms of V.


Homework Equations


pH = -log[H]


The Attempt at a Solution


a) pH = -log(2) which is interestingly a negative number so I hope this is correct.
b) I'm not sure how you would do this part. Do we just find the new concentration in terms of V and then find the negative log of that? Don't we have to consider the autoionization of water?

Thanks!

BiP
 
Physics news on Phys.org
  • #2
Yes, negative pH is possible.

Check the link I posted in your other thread for the way pH should be calculated. And read about dilution calculation.
 

1. What is the relationship between volume and pH in an HCl solution?

The pH of an HCl solution is directly proportional to the volume of the solution. As the volume increases, the pH decreases and becomes more acidic. This is because HCl is a strong acid and dissociates completely in water, increasing the concentration of H+ ions and decreasing the pH.

2. How does the concentration of HCl affect the pH of the solution?

The concentration of HCl has a direct impact on the pH of the solution. A higher concentration of HCl will result in a lower pH, making the solution more acidic. Conversely, a lower concentration of HCl will result in a higher pH, making the solution less acidic.

3. Can the pH of an HCl solution change as the volume increases?

Yes, the pH of an HCl solution can change as the volume increases. As more water is added, the concentration of H+ ions decreases, resulting in a higher pH. However, this change may not be significant unless the volume is significantly increased or the initial concentration of HCl is very high.

4. How can the pH of an HCl solution be measured?

The pH of an HCl solution can be measured using a pH meter or pH indicator strips. A pH meter measures the voltage of the solution and converts it into a pH value, while pH indicator strips change color based on the pH of the solution.

5. What is the pH of a 1M HCl solution?

A 1M (1 molar) HCl solution has a pH of 0. This is because a 1M solution contains 1 mole of HCl per liter of solution, resulting in a high concentration of H+ ions and a very low pH.

Similar threads

  • Biology and Chemistry Homework Help
Replies
3
Views
1K
  • Biology and Chemistry Homework Help
Replies
1
Views
1K
  • Biology and Chemistry Homework Help
Replies
9
Views
2K
  • Biology and Chemistry Homework Help
Replies
8
Views
2K
  • Biology and Chemistry Homework Help
Replies
22
Views
5K
  • Biology and Chemistry Homework Help
Replies
2
Views
2K
  • Biology and Chemistry Homework Help
Replies
11
Views
2K
  • Biology and Chemistry Homework Help
Replies
4
Views
1K
  • Biology and Chemistry Homework Help
Replies
4
Views
1K
  • Biology and Chemistry Homework Help
Replies
20
Views
2K
Back
Top