Answer:
[tex]0.000056[/tex]
Explanation:
If [tex]pH[/tex] is given then hydronium ion concentration is equal to [tex]-log[H_3O^+][/tex]
The hydronium ion concentration can be found from the pH using the following formula:
Hydronium ion concentration = [tex]10^{-pH}[/tex]
As the pH of a HClO4 solution was measured as 4.251,
put [tex]pH=4.251[/tex]
So,
Concentration of HClO4 in the solution = [tex]10^{-4.251}=0.000056[/tex]