430 mL of 0.044 M perchloric acid is added to 681 mL of 0.085 M hydroiodic acid. Calculate the pH of the resulting solution of strong acids at 25 °C.
Please help.
I am confused on how to do this
what is wrong with computing the conc H+ due to each acid, then adding them, and from that sum H+, calculating pH?
I did that! but my answer was wrong
To calculate the pH of the resulting solution, we need to consider the properties of strong acids and their reaction with water.
Step 1: Write the balanced chemical equation for the reaction between perchloric acid (HClO4) and hydroiodic acid (HI).
HClO4 + HI → H2O + ClO4- + I-
Step 2: Determine the moles of each acid.
The moles of perchloric acid (HClO4) can be calculated using the equation:
moles of HClO4 = volume (L) x concentration (M)
moles of HClO4 = 0.430 L x 0.044 M = 0.01892 mol
The moles of hydroiodic acid (HI) can be calculated using the equation:
moles of HI = volume (L) x concentration (M)
moles of HI = 0.681 L x 0.085 M = 0.05799 mol
Step 3: Determine the total volume of the resulting solution.
The total volume can be calculated by adding the volumes of the two acids:
total volume = volume of HClO4 + volume of HI
total volume = 0.430 L + 0.681 L = 1.111 L
Step 4: Calculate the concentration of the resulting solution.
The concentration of the resulting solution can be calculated by dividing the total moles by the total volume:
concentration of resulting solution = total moles / total volume
concentration of resulting solution = (moles of HClO4 + moles of HI) / total volume
concentration of resulting solution = (0.01892 mol + 0.05799 mol) / 1.111 L
concentration of resulting solution = 0.07391 M
Step 5: Determine the concentration of the hydronium ion (H3O+).
Since we have a solution of a strong acid, the concentration of the hydronium ion will be equal to the concentration of the acid.
concentration of H3O+ = concentration of resulting solution
concentration of H3O+ = 0.07391 M
Step 6: Calculate the pH of the resulting solution using the formula:
pH = -log[H3O+]
pH = -log(0.07391)
pH = 1.13
Therefore, the pH of the resulting solution of strong acids is approximately 1.13 at 25 °C.