In order to determine the concentration of a solution of Carbonic Acid (H2CO3), a sample was placed in a buret and titrated with 0.1132 M Sodium hydroxide. For the carbonic acid, the initial reading was 11.0ml and final reading was 31.0 ml. For sodium Hydroxide, the initial reading was 1.2 and the final reading was 46.4ml. What is the concentration of the carbonic acid?

Question

In order to determine the concentration of a solution of Carbonic Acid (H2CO3), a sample was placed in a buret and titrated with 0.1132 M Sodium hydroxide. For the carbonic acid, the initial reading was 11.0ml and final reading was 31.0 ml. For sodium Hydroxide, the initial reading was 1.2 and the final reading was 46.4ml. What is the concentration of the carbonic acid?

Answer 1

To determine the concentration of the carbonic acid (H2CO3) solution, we can use the concept of titration. Titration involves the reaction between the acid and a base of known concentration to determine the concentration of the acid.

Given:
- Volume of carbonic acid solution used: initial reading = 11.0 mL, final reading = 31.0 mL
- Concentration of sodium hydroxide (NaOH) solution used: 0.1132 M
- Volume of sodium hydroxide solution used: initial reading = 1.2 mL, final reading = 46.4 mL

Here's how we can calculate the concentration of the carbonic acid solution:

1. Determine the volume of sodium hydroxide used:
Volume of sodium hydroxide used = final reading - initial reading
Volume of sodium hydroxide used = 46.4 mL - 1.2 mL = 45.2 mL

2. Convert the volume of sodium hydroxide used to liters:
Volume of sodium hydroxide used = 45.2 mL * (1 L / 1000 mL)
Volume of sodium hydroxide used = 0.0452 L

3. Use the balanced chemical equation to determine the stoichiometry between the acid and the base:
H2CO3 + 2NaOH -> Na2CO3 + 2H2O

From the balanced equation, we can see that one mole of carbonic acid reacts with two moles of sodium hydroxide.

4. Calculate the number of moles of sodium hydroxide used:
Moles of sodium hydroxide = concentration of sodium hydroxide * volume of sodium hydroxide used
Moles of sodium hydroxide = 0.1132 M * 0.0452 L

5. Use the stoichiometry to determine the number of moles of carbonic acid:
Moles of H2CO3 = (moles of sodium hydroxide) / 2

6. Calculate the concentration of carbonic acid:
Concentration of H2CO3 = moles of H2CO3 / volume of carbonic acid used
Concentration of H2CO3 = (moles of H2CO3) / (final reading - initial reading)

Plug in the values:

Concentration of H2CO3 = (moles of H2CO3) / (31.0 mL - 11.0 mL)
Concentration of H2CO3 = (0.1132 M * 0.0452 L) / 20.0 mL
Concentration of H2CO3 = (0.005113 mMol) / 0.020 L
Concentration of H2CO3 = 0.2557 M

Therefore, the concentration of the carbonic acid (H2CO3) solution is approximately 0.2557 M.

Answer 2

H2CO3 + 2NaOH ==> Na2CO3 + 2H2O OR

H2CO3 + NaOH ==> NaHCO3 + H2O

This problem is not workable with the information given. The titration of H2CO3 has TWO endpoints as shown in the two equations above. If phenolphthalein is used as the indicator the second equation is in effect. If methyl red indicator is used it's the first equation.