how to find ph of aqueous solution if your only given the concentration
When you don't give a specific question it is tough to answer. This is a general question and has two or three answers depending upon what the aq solution is.
If it is a solution of an acid or base it is done one way. If it is a salt which has hydrolyzed it is done another way. Do you have a preference? I'm not too interested in doing both.
What is the pH of an aqueous solution that is 8.5*10^-2 M NaOCl?
The Na^+ is not hydrolyzed. The OCl^- is hydrolyzed.
........OCl^- + HOH ==> HOCl + OH^-
I.......0.085...........0........0
C.........-x............x.......x
E.......0.085-x........x.........x
Kb for OCl^- = (Kw/Ka for HOCl) = (HOCl)(OH^-)/(OCl^-)
Substitute from the ICE chart into the Kb for OCl^- expression and solve for x = (HOCl) = (OH^-).
Use OH^- to solve for pOH = -log(OH^-) then pH + pOH = pKw = 14.Solve for pH.
To find the pH of an aqueous solution if you are only given the concentration, you can use the equation for calculating pH:
pH = -log[H+]
Here are the steps to follow:
1. Determine the concentration of the hydrogen ion, [H+], in the solution. This concentration is usually given in moles per liter (M) or in some cases, might be given in another unit such as millimoles per liter (mM).
2. Take the negative logarithm (base 10) of the concentration of [H+]. This can be done using a scientific calculator. If you don't have a calculator, you can use logarithm tables or an online logarithm calculator.
3. The result will be the pH of the solution. Keep in mind that pH is a dimensionless quantity, representing the concentration of hydrogen ions on a logarithmic scale ranging from 0 to 14. A pH less than 7 is acidic, a pH greater than 7 is basic, and a pH of 7 is neutral.
Note: If you are given the concentration of the hydroxide ion [OH-] instead of [H+], you can still find the pH by first calculating the pOH using the same steps and then subtracting the pOH from 14. pH + pOH = 14