The Ka of hypochlorous acid (HClO) is 3.00×10-8 at 25.0°C. Calculate the pH of a 0.0385 M hypochlorous acid solution.
A.1.41
B.7.52
C.-1.41
D.4.47
E.8.94
I chose B
3 answers
B isn't right and you should know not to pick that. pH of 7.51 is basic and this is an acid. If you will show your work I will find where you went wrong.
I think i figured it out
0.0385
change
-x. . . . .. . +x. . . .+x
at equilibrium
0.0385-x. .. x..... . .x
Ka = 3.0 x 10^-8 = [H+][ClO-]/ [HClO]= (x)(x)/ 0.0385-x
x = [H+]= 3.4 x 10^-5 M
pH = - log 3.4 x 10^-5=4.5
Im going with D now
0.0385
change
-x. . . . .. . +x. . . .+x
at equilibrium
0.0385-x. .. x..... . .x
Ka = 3.0 x 10^-8 = [H+][ClO-]/ [HClO]= (x)(x)/ 0.0385-x
x = [H+]= 3.4 x 10^-5 M
pH = - log 3.4 x 10^-5=4.5
Im going with D now
D is right.
3 answers