The [H3O+] of 0.116 M H3C6H5O7 can be calculated using the Henderson-Hasselbalch equation:
[H3O+] = Ka1 x [H3C6H5O7] / (Ka1 - Ka2)
= 7.4 x 10-4 x 0.116 / (7.4 x 10-4 - 1.7 x 10-5)
= 0.0114 M
Calculate the [H3O+] and pH of each polyprotic acid solution.
(b) 0.116 M H3C6H5O7
I did part (a) just fine, but for some reason can't figure (b) out. Can someone help me with just the [H3O+] part to get me started?
I already got 9.3e-3 and 1.4e-3 without success and only have one try left.
The Ka values according to the appendix given are Ka1=7.4x10-4, Ka2=1.7x10-5, Ka3=4.0x10-7.
Thank you so much.
1 answer