The buildup of lactic acid in muscles causes pain during extreme physical exertion. the ka for lactic acid (c2h5ocooh) is 8.4 * 10-4. calculate the ph of a 0.06 m solution of lactic acid. 1. 2.297 2. 11.851 3. 2.174 4. 2.043 5. 2.149 6. 6.348 7. 1.926 8. 3.533

Question

Chemistry

Mallory Bentley

17 June, 19:15

The buildup of lactic acid in muscles causes pain during extreme physical exertion. the ka for lactic acid (c2h5ocooh) is 8.4 * 10-4. calculate the ph of a 0.06 m solution of lactic acid. 1. 2.297 2. 11.851 3. 2.174 4. 2.043 5. 2.149 6. 6.348 7. 1.926 8. 3.533

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Ronald Logan · Answer 1

Answer is: pH of lactic acid is: 3. 2.174.

Chemical reaction: C₃H₆O₃ (aq) ⇄ C₃H₅O₃⁻ (aq) + H⁺ (aq).

c (lactic acid - C₃H₆O₃) = 0,06 M.

Ka (C₃H₆O₃) = 8.4·10⁻⁴.

[H⁺] = [C₃H₅O₃⁻ ] = x.

[C₃H₆O₃ ] = 0.06 M - x.

Ka = [C₃H₅O₃⁻] · [H⁺] / [C₃H₆O₃ ].

8.4·10⁻⁴ = x² / (0.06 M - x).

Solve quadratic equation: x = [H⁺] = 0.0067 M.

pH = - log[H⁺].

pH = - log (0.0067 M) = 2.17.