Posted by **Nat** on Friday, July 5, 2013 at 11:52pm.

The pH of a 0.10 M solution of a certain acid is 3.25 at 25°C. What is the pH of a 0.010 M solution of the same acid at the same temperature?

- Chemistry -
**DrBob222**, Saturday, July 6, 2013 at 12:18am
pH = -log(H^+)

-3.25 = log(H^+)

Solve for (H^+). I estimated 5E-4 but you need to be more accurate than that.

..........HA ==> H^+ + A^-

I.........0.1.....0.....0

C.........-x.....x.....x

E......-0.1-x....x......x

and you know x = 5E-4 from above (again that is an estimate)

Ka = (H^+)(A^-)/(HA)

Solve for Ka.

Then .....HA ==> H^++ A^-

I........0.01.....0....0

C.........-x.....x......x

E......0.01-x.....x.....x

Substitute the E line into Ka expression along with Ka determined from the first part and solve for x = (H^+), then convert to pH.

- Chemistry -
**Nat**, Saturday, July 6, 2013 at 12:35am
Oh I see what I did wrong! I got the answer 3.75. Thanks for the help!

## Answer this Question

## Related Questions

- Chemistry - The pH of a 0.10 M solution of a certain acid is 3.25 at 25°C. What ...
- Chemistry - The pH of a 0.10 M solution of a certain acid is 3.25 at 25°C. What ...
- chemistry- Thank you - Suppose you add 81 ml of dilute acid to 54 ml of water. ...
- chemistry - Suppose you add 92 ml of dilute acid to 46 ml of water. Both the ...
- College Chemistry - Science - At room temperature (25°C), 45 mL of a 0.002 M ...
- Chemistry - Trichloroacetic acid (CCl3CO2H) is a corrosive acid that is used to ...
- chemistry - A 0.010 M solution of a weak monoprotic acid has a pH of 3.70. What ...
- Algebra - 100mL of a solution contains 30 mL of acid; this is called a 30% acid ...
- Solving Rational Equations - 100mL of a solution contains 30 mL of acid; this is...
- Algebra - Suppose a 2% acid solution is mixed with a 3% acid solution. Find the ...