1.77828 x 10^-9 is what my calculator shows. Do you know how to do this on the calculator? put in 8.75 and change to a - OR enter -8.75 initially. Then hit the 10x key and up will pop 1.77828 x 10^-9. Logically, wouldn't you expect pH = 9.00 to be 1 x 10^-9?. 8.75 is just a little more acid than that.
