the pH of 10^-8 M of HCL
Answers
Answer:
The answer is a number just less than 7. Since Hcl is a strong acid the pH can never be greater than 7.
Explanation:The concentration of HCl = 10−8 M
Total [H+] = [H+] obtained from HCL +[H+] obtained from H2O
HCl being strong acid, it completely ionizes.
[H+] HCl = 1.0 x 10-8.
The concentration of H+ from ionization is equal to the [OH–] from water and let us consider it is equal to x.
[H+] H2O = [OH–] H2O = x
Total [H+] = x + 1.0 x 10-8………………………(1)
But we know
[H+] [OH–] = 1.0 x 10-14
(1.0 x 10-8 + x) (x) = 1.0 x 10-14
X2 + 10-8 x – 10-14 = 0
Solving x we get
x = 9.5 x 10-8
Substituting x value in equation (1)
Total [H+] = 9.5 x 10-8 + 1.0 x 10-8
Total [H+] = 1.05 x 10-7.
Consider an equation
pH = – log [H+]
pH = – log [1.05 x 10-7]
pH = 6.98