If you have CL2 + H2o ---> H+ + Cl- + HOCl
and you are given [HOCl] = 0.06 M
and you have to find pH....
can you assume that [HOCl] =[H+] = 0.06 M
since H+ and HOCl both have a coefficient of 1?
Thank you
Answered elsewhere.
So if I can't assume that, then how can I calclate pH? I don't know K value, so I can't use Henderson Hasselbalc...
Kiki--It's the next day and I have a clearer head than when I read your problem the first time last night. I just did not read your question properly (and the small o in H2o threw me off, too). Of course, if HOCl is 0.06 M, then H^+ is 0.06 M and Cl^- is 0.06 M. You may want to recognize that HOCl is a weak acid; therefore, it will provide some hydrogen ions additional to the H^+ and Cl^- from the reaction but the amount will be decreased, due to Le Chatelier's principle. That is
HOCl ==> H^+ + OCl^-
Ka = (H^+)(OCl^-)/(HOCl)
If (H^+) = 0.06 = (HOCl), then (OCl^-) = Ka
Total H^+ then is 0.06 from HCl part and Ka (whatever that value is) from the HOCl part. I suspect the H^+ from HOCl will be so small that it is negligible.
No, you cannot assume that [HOCl] = [H+] = 0.06 M just because they both have a coefficient of 1. In this reaction, the equation indicates that one molecule of HOCl dissociates to produce one H+ ion and one Cl- ion. However, the initial concentration of HOCl does not necessarily determine the concentration of H+.
To find the pH, you need to calculate the concentration of H+ using the given value of [HOCl]. The dissociation of HOCl can be represented by the equation: HOCl <--> H+ + OCl-.
The dissociation constant for HOCl, also called the acid dissociation constant (Ka), can be used to relate the concentrations of the species in the equation. The Ka expression for HOCl is:
Ka = [H+][OCl-] / [HOCl]
In this case, you are given that [HOCl] = 0.06 M. Therefore, [H+] and [OCl-] are the unknowns that need to be determined to calculate the pH.
To solve for [H+], you can rearrange the Ka expression:
[H+][OCl-] = Ka * [HOCl]
Since [OCl-] is equal to [H+], you can substitute [H+] for [OCl-]:
[H+]^2 = Ka * [HOCl]
Now, you can solve for [H+] by taking the square root of both sides:
[H+] = sqrt(Ka * [HOCl])
Next, plug in the known values:
[H+] = sqrt(Ka * 0.06 M)
Finally, calculate the square root of Ka * 0.06 M to find the concentration of H+. Once you have [H+], you can find the pH using the formula pH = -log[H+].