calculate the pH at 25 degrees of 0.080 mol dm^-3 HNO3
To calculate the pH of a solution of HNO3 (nitric acid) at a given concentration and temperature, we can use its dissociation constant and the equation for calculating pH.
First, let's find the dissociation constant for HNO3 at 25 degrees Celsius. The dissociation constant of an acid, denoted as Ka, indicates the extent to which it dissociates in water. The Ka value for HNO3 is approximately 24 × 10^6 mol dm^-3.
Now, we can use the equation for calculating pH:
pH = -log[H3O+]
In the case of HNO3, it is a strong acid and completely dissociates in water. Therefore, the concentration of H3O+ ions produced is equal to the initial concentration of HNO3.
So, the pH of the solution is given by:
pH = -log[0.080]
Calculating this, we get:
pH = -log(0.080) ≈ 1.10
Therefore, the pH of a 0.080 mol dm^-3 HNO3 solution at 25 degrees Celsius is approximately 1.10.