Perchloric acid, HClO4, is a strong acid. What are the pH values of the
following solutions:
a) 3 M perchloric acid
b) 0.1 M perchloric acid
c) 0.001234 M perchloric acid
d) 10-5 M perchloric acid
e) 10-9 M perchloric acid
is the pH -log(conc. ?
If you input the = sign in the right place it is.
Yes, the pH is calculated using the logarithm of the concentration of hydronium ions ([H3O+]) in a solution. The hydronium ion concentration is related to the concentration of the strong acid ([HClO4]) in the solution.
To calculate the pH, you can use the equation:
pH = -log[H3O+]
To find the concentration of hydronium ions ([H3O+]), you need to know the concentration of the strong acid [HClO4]. In the case of perchloric acid (HClO4), it completely dissociates in water to form hydronium and perchlorate ions:
HClO4(aq) → H+(aq) + ClO4-(aq)
Now, let's calculate the pH values for each given concentration:
a) 3 M perchloric acid:
Since the concentration is 3 M, it means that the concentration of hydronium ions ([H3O+]) is also 3 M. Therefore, the pH is calculated as:
pH = -log(3) ≈ 0.522
b) 0.1 M perchloric acid:
Similarly, since the concentration is 0.1 M, the concentration of hydronium ions ([H3O+]) is also 0.1 M. Therefore, the pH is:
pH = -log(0.1) = 1
c) 0.001234 M perchloric acid:
The concentration of hydronium ions ([H3O+]) is equal to the concentration of the strong acid, so it is 0.001234 M. Therefore, the pH is:
pH = -log(0.001234) ≈ 2.908
d) 10-5 M perchloric acid:
Here, the concentration of hydronium ions ([H3O+]) is equal to the concentration of the strong acid, so it is 10-5 M. Therefore, the pH is:
pH = -log(10-5) = 5
e) 10-9 M perchloric acid:
Similarly, in this case, the concentration of hydronium ions ([H3O+]) is equal to the concentration of the strong acid, so it is 10-9 M. Therefore, the pH is:
pH = -log(10-9) = 9
Remember, pH values range from 0 to 14, with values less than 7 considered acidic, 7 considered neutral, and values greater than 7 considered basic.