Carbonic acid, H₂CO₃ is a diprotic acid with Ka1 = 4. 3 × 10⁻⁷ and Ka2 = 5. 6 × 10⁻¹¹. What is the pH of a 0. 47 M solution of carbonic acid?

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Lanuel

Based on the calculations, the pH of a 0.47 M solution of carbonic acid (H₂CO₃) is equal to 3.35.

How to calculate the pH of a solution?

First of all, we would write a properly balanced chemical equation for these chemical reactions:

                   H₂CO₃(aq)  ⇄ HCO₃⁻(aq) + H⁺(aq);   Ka₁ = 4.3 × 10⁻⁷.

For the second chemical reaction:

                   HCO₃⁻(aq) ⇄ CO₃²⁻(aq) + H⁺(aq);      Ka₂ = 5.6 × 10⁻¹¹.

Next, we set up an equation from the ICE table;

[HCO₃⁻] = [H⁺] = x.

[H₂CO₃] = 0.47 - x.

Ka₁ = ([HCO₃⁻] × [H⁺])/[H₂CO₃].

4.3 × 10⁻⁷ = (x × x)/(0.47 - x).

4.3 × 10⁻⁷ = x²/(0.47 - x).

x² = 0.0000002021 - 4.3 × 10⁻⁷x

x² + 4.3 × 10⁻⁷x - 0.0000002021 = 0

By solving the quadratic equation, we have:

x = [H⁺] =0.000449 M.

Now, we can determine the pH by using this formula;

pH = -log[H⁺]

pH = -log(0.000449 M).

pH = -(-3.35)

pH = 3.35.

Note: The second dissociation from Ka₂ would be so small, so it's considered negligible.

Read more on pH here: brainly.com/question/24233266

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