A What is the H concentration for an aqueous solution withpH

A. What is the H+ concentration for an aqueous solution withp)H = 2.74 at 25 degrees C. ?

B.Arrange the following aqueous solutions, all at 25 Degrees C , in order of decreasing acidity. pH= 5.45 , .0023 M HCl , pOH= 8.55, .0018 M KOH

Solution

A.

[H+] = 10^-pH = 10^-2.74 = 1.9 x 10^-3 M

B.

Knowing 2 things, lower pH, stronger acid. Low as in around 1-3 on pH scale, now this is easy.

KOH...in water it becomes K+ and OH-. OH- is a STRONG base, very high pH.
pOH = 14-pH. So pOH = 8.55 means pH = 5.45, same as the other

KOH
5.45, 5.45