18.0 ml of 0.122 M diprotic acid was titrated with 0.1017 M NaOH. The acid ionization constants for the acid are Ka1 = 5.210^-5 and ka2 = 3.410^-10. At what added volume of base does the first equivalence point occur?

Question

18.0 ml of 0.122 M diprotic acid was titrated with 0.1017 M NaOH. The acid ionization constants for the acid are Ka1 = 5.210^-5 and ka2 = 3.410^-10. At what added volume of base does the first equivalence point occur?

Answer 1

H2A + NaOH ==> NaHA + H2O for the first H.

NaHA + NaOH ==> Na2A + H2O for the 2nd H.

mols H2SO4 = 0.018L x 0.122 M = ?
mols NaOH = same for the first H.
M NaOH = moles NaOH/L NaOH. Solve for L NaOH.

Answer 2

To determine the volume of NaOH required to reach the first equivalence point in the titration, we need to calculate the number of moles of acid (diprotic acid) present in the initial solution. Then, we can determine the volume of NaOH needed to react exactly with all of the acid.

First, let's calculate the number of moles of acid in the initial solution:

moles of acid = volume of acid (in liters) × concentration of acid (in mol/L)

Given:
Volume of acid = 18.0 mL = 18.0 × 10^(-3) L
Concentration of acid = 0.122 M

moles of acid = 18.0 × 10^(-3) L × 0.122 mol/L

Next, we need to determine the stoichiometry of the reaction between the diprotic acid and the NaOH. From the question, we know that the acid is diprotic, meaning it can release two protons (H+ ions) per molecule.

The balanced chemical equation for the reaction can be represented as:
H2A + 2NaOH → Na2A + 2H2O

Here, H2A represents the diprotic acid.

According to the equation, each mole of H2A reacts with 2 moles of NaOH. Therefore, the number of moles of NaOH required to react with the acid is:

moles of NaOH = 2 × moles of acid

Now, we can calculate the moles of NaOH required:

moles of NaOH = 2 × (18.0 × 10^(-3) L × 0.122 mol/L)

Next, we can use the volume and concentration of NaOH to determine the volume of NaOH required to react with the acid. The stoichiometry of the reaction suggests that one mole of NaOH reacts with one mole of acid (H2A).

The volume of NaOH required can be calculated using the formula:

volume of NaOH = moles of NaOH / concentration of NaOH

Given:
Concentration of NaOH = 0.1017 M

volume of NaOH = (2 × (18.0 × 10^(-3) L × 0.122 mol/L) / 0.1017 mol/L

Now, calculate the volume of NaOH required to reach the first equivalence point.

18.0 ml of 0.122 M diprotic acid was titrated with 0.1017 M NaOH. The acid ionization constants for the acid are Ka1 = 5.2*10^-5 and ka2 = 3.4*10^-10. At what added volume of base does the first equivalence point occur?

H2A + NaOH ==> NaHA + H2O for the first H.

To determine the volume of NaOH required to reach the first equivalence point in the titration, we need to calculate the number of moles of acid (diprotic acid) present in the initial solution. Then, we can determine the volume of NaOH needed to react exactly with all of the acid.

18.0 ml of 0.122 M diprotic acid was titrated with 0.1017 M NaOH. The acid ionization constants for the acid are Ka1 = 5.210^-5 and ka2 = 3.410^-10. At what added volume of base does the first equivalence point occur?