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? Note: phenolphthalein is used as the indicator

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? Note: phenolphthalein is used as the indicator

Answer 1

To determine the concentration of the carbonic acid solution, you can use the concept of stoichiometry and the volume of the titrant (Sodium hydroxide) used.

The balanced chemical equation for the reaction between carbonic acid (H2CO3) and sodium hydroxide (NaOH) is:

H2CO3 + 2NaOH → Na2CO3 + 2H2O

Since one mole of carbonic acid reacts with two moles of sodium hydroxide, the molar ratio between H2CO3 and NaOH is 1:2. This means that for every mole of H2CO3, two moles of NaOH are consumed.

In the titration, the volume of NaOH used can be calculated by subtracting the initial and final buret readings:

Volume of NaOH used = Final reading - Initial reading

Volume of NaOH used = 46.4 ml - 1.2 ml = 45.2 ml

Next, we can calculate the moles of NaOH used in the reaction:

Moles of NaOH = (Volume of NaOH used) x (Molarity of NaOH)

Moles of NaOH = 45.2 ml x 0.1132 M = 5.11384 mmol (millimoles)

Since the molar ratio between H2CO3 and NaOH is 1:2, the moles of H2CO3 present in the titration will be half the moles of NaOH used:

Moles of H2CO3 = (Moles of NaOH) / 2

Moles of H2CO3 = 5.11384 mmol / 2 = 2.55692 mmol

Finally, we can calculate the concentration of the carbonic acid solution by dividing the moles of H2CO3 by the volume of the solution titrated:

Concentration of H2CO3 = (Moles of H2CO3) / (Volume of Solution Titrated)

To calculate the volume of the H2CO3 solution titrated, subtract the initial and final buret readings:

Volume of H2CO3 solution titrated = Final reading - Initial reading

Volume of H2CO3 solution titrated = 31.0 ml - 11.0 ml = 20.0 ml

Now we can calculate the concentration of H2CO3:

Concentration of H2CO3 = 2.55692 mmol / 20.0 ml

Concentration of H2CO3 = 0.1278 M

Therefore, the concentration of the carbonic acid solution is approximately 0.1278 M.

Answer 2

To determine the concentration of the carbonic acid (H2CO3) solution, you can use the equation:

H2CO3 + 2 NaOH -> Na2CO3 + 2 H2O

First, let's calculate the volume of sodium hydroxide (NaOH) used in the titration.

Volume of NaOH used = Final reading - Initial reading
= 46.4 ml - 1.2 ml
= 45.2 ml

Next, let's calculate the number of moles of NaOH used.

Moles of NaOH = Molarity of NaOH * Volume of NaOH used
= 0.1132 M * (45.2 ml / 1000 ml/L)
= 0.005115 moles

Since the balanced equation shows a 1:1 stoichiometric ratio between NaOH and H2CO3, the number of moles of H2CO3 is also 0.005115 moles.

Now, let's calculate the volume of carbonic acid (H2CO3) used.

Volume of H2CO3 used = Final reading - Initial reading
= 31.0 ml - 11.0 ml
= 20.0 ml

Finally, we can calculate the concentration of the carbonic acid solution.

Concentration of H2CO3 = Moles of H2CO3 / Volume of H2CO3 used
= 0.005115 moles / (20.0 ml / 1000 ml/L)
= 0.25575 M

Therefore, the concentration of the carbonic acid (H2CO3) solution is 0.25575 M.