HA and HB are two strong monobasic acids. 25cm3 of 6moldm-3 Ha is mixed with 45cm3 of 3moldm-3 HB. What is the H+ concentration in moldm-3 in the resting solution
25cm^3 * 6mol/L = 0.15 moles of HA
45cm^3 * 3mol/L = 0.135 moles of HB
That will leave 0.015 moles of HA
Now you can get the pH of that.
To determine the H+ concentration in the resulting solution, we need to perform a mole-to-mole comparison between the two acids.
First, let's find the number of moles of H+ in each acid:
For acid HA:
Volume (V) = 25 cm³
Concentration (C) = 6 mol/dm³
Number of moles (n) = V * C
n(HA) = (25/1000) dm³ * 6 mol/dm³
n(HA) = 0.15 mol
For acid HB:
Volume (V) = 45 cm³
Concentration (C) = 3 mol/dm³
Number of moles (n) = V * C
n(HB) = (45/1000) dm³ * 3 mol/dm³
n(HB) = 0.135 mol
Now, we have the moles of H+ in each acid, let's find the total moles of H+ in the resulting solution:
n(total) = n(HA) + n(HB)
n(total) = 0.15 mol + 0.135 mol
n(total) = 0.285 mol
Finally, let's calculate the concentration of H+ in the solution:
Volume (V) = 25 cm³ + 45 cm³ = 70 cm³
Concentration (C) = n(total) / V
C(H+) = 0.285 mol / (70/1000) dm³
C(H+) = 4.07 mol/dm³
Therefore, the H+ concentration in the resulting solution is 4.07 moldm-3.
To find the H+ concentration in the resulting solution, we first need to determine the number of moles of H+ ions present in each acid solution.
For HA:
Volume of HA solution = 25 cm^3
Molarity of HA = 6 moldm^-3
Using the formula: Moles = Volume × Molarity
Moles of H+ in HA = 25 cm^3 × (6 moldm^-3) = 150 × 10^-3 moles
Similarly, for HB:
Volume of HB solution = 45 cm^3
Molarity of HB = 3 moldm^-3
Moles of H+ in HB = 45 cm^3 × (3 moldm^-3) = 135 × 10^-3 moles
Now, to find the total moles of H+ ions in the resulting solution, we sum up the moles of H+ from both acids:
Total moles of H+ = Moles of H+ in HA + Moles of H+ in HB
= 150 × 10^-3 moles + 135 × 10^-3 moles
= 285 × 10^-3 moles
Next, we need to calculate the total volume of the resulting solution by adding the volumes of both acid solutions:
Total volume of resulting solution = Volume of HA solution + Volume of HB solution
= 25 cm^3 + 45 cm^3
= 70 cm^3
Finally, to find the H+ concentration in the resulting solution, we divide the total moles of H+ ions by the total volume of the solution in dm^3:
H+ concentration = Total moles of H+ / Total volume of solution
H+ concentration = (285 × 10^-3 moles) / (70 × 10^-3 dm^3)
= 4.07 moldm^-3
Therefore, the H+ concentration in the resulting solution is 4.07 moldm^-3.