Chemistry
posted by Jill .
how do I determine the Ka for an acid HX if th epH of a 1.00M solution of HX is 4.5

pH = log(H^+).
Substitute and solve for (H^+)
......HX ==> H^+ + X^
I.....1.0M....0....0
C......x.....x.....x
E....1.0x.....x....x
Ka = (H^+)(X^)/HX
x= (H^+) from the pH part. Substitute and solve for Ka.