A solution is prepared by adding 50ml of 0.050M HCl to 150 ml of 0.10M HNO3. Calculate pH
.050 L * .050 M = .0025 moles ... .150 L * .10 M = .015 moles
... total moles H+ ... .0175
total solution volume ... .050 L + .150 L = .20 L
[H+] = .0175 moles / .20 L = ?
pH = -1 * log[H+]
the two strong acids fully dissociate
divide the total moles of H+ by the total solution volume
... this is the concentration of H+ ... [H+]
pH is the negative logarithm of [H+]
To calculate the pH of the solution, we need to determine the concentration of H+ ions in the solution.
First, we need to calculate the moles of HCl and HNO3 used.
The moles of HCl can be calculated as follows:
moles of HCl = concentration of HCl (in M) * volume of HCl (in L)
moles of HCl = 0.050 M * 0.050 L = 0.0025 moles
Similarly, the moles of HNO3 can be calculated as follows:
moles of HNO3 = concentration of HNO3 (in M) * volume of HNO3 (in L)
moles of HNO3 = 0.10 M * 0.150 L = 0.015 moles
Next, we need to determine the total moles of H+ ions. Since HCl and HNO3 are strong acids, they dissociate completely in water. This means that each mole of HCl and HNO3 will produce one mole of H+ ions.
The total moles of H+ ions in the solution is the sum of moles of HCl and HNO3:
total moles of H+ ions = moles of HCl + moles of HNO3
total moles of H+ ions = 0.0025 moles + 0.015 moles = 0.0175 moles
To calculate the concentration of H+ ions in the solution, we divide the total moles of H+ ions by the total volume of the solution (in liters):
concentration of H+ ions = total moles of H+ ions / total volume of solution
concentration of H+ ions = 0.0175 moles / (0.050 L + 0.150 L)
concentration of H+ ions = 0.0175 moles / 0.200 L = 0.0875 M
Finally, to calculate the pH, we use the formula:
pH = -log[H+]
pH = -log(0.0875)
pH ≈ 1.058
Therefore, the pH of the solution is approximately 1.058.