[Giudy89]

I have two problems that I can not solve, if you help me I shall be grateful.:
1) 25ml of 0.15M HClO mixed with 25ml of 0.15M NaOH. Calculate the pH of the final solution.

I found the moles of CH3COOH ie 0.005mol
Then I calculated the molar with the total volume, and I have results as 0.1M.
After I found the [OH-] by (Kb of CH3COO-* M) '1 / 2 and with the result, I calculated pOH and pH, but the result is different from that of my teacher .. my result is pH= 9,946 but the result of my teacher is pH = 10:18
tell me where wrong!

2) in a solution of a weak acid 0.2M, the concentration of ions A-is 6.5 * 10 (-3) M. calculate the Ka. here are in trouble .. not even know where to start. I need to replace the data in the formula to find the Ka?

[Borek]

1. Question uses HClO, you have calculated for CH3COOH. Teacher result is OK.

2. This is all in dissociation stoichiometry. What is concentration of H⁺ if concentration of A^- is 6.5x10^-3M? What is concentration of HA?

[Giudy89]

sorry sorry sorry... I did many exercise with CH3COOH and I mistake.. I I took the wrong value in the table.. sorry!!