Suppose that 0.10 liter of 0.50 molar hydrochloric acid is added to 0.040 liter of the buffer

prepared in (b). Compute the hydrogen ion concentration of the resulting solution.

1 answer

First, let's find the moles of HCl added:

moles HCl = volume (in liters) x molarity
moles HCl = 0.10 L x 0.50 mol/L
moles HCl = 0.05 mol

Next, let's find the moles of the buffer components in 0.040 L:

moles of HA = volume (in liters) x molarity
moles of HA = 0.040 L x 0.50 mol/L
moles of HA = 0.020 mol

moles of A- = volume (in liters) x molarity
moles of A- = 0.040 L x 0.50 mol/L x 0.10
moles of A- = 0.002 mol

To calculate the hydrogen ion concentration of the resulting solution, we need to find the total moles of H+ and the total volume of the solution. The HCl will completely dissociate in water, so all of its moles will contribute to the hydrogen ion concentration:

total moles of H+ = 0.05 mol (from HCl) + 0.002 mol (from A-)
total volume = 0.10 L + 0.040 L = 0.14 L

Now we can calculate the hydrogen ion concentration:

[H+] = moles of H+ / volume of solution
[H+] = (0.05 mol + 0.002 mol) / 0.14 L
[H+] = 0.37 M

Therefore, the hydrogen ion concentration of the resulting solution is 0.37 M.