Which of the following weak acids would make the best buffer at pH = 5.0? A)acetic acid (K_a= 1.74 × 10-5,pK_a= 4.76) B)bicarbonate (K_a = 6.3 × 10-11,pK_a = 10.24) C)tris-hydroxymethyl aminomethane (K_a = 8.32 × 10-9,pK_a = 8.07) D)lactic acid (K_a = 1.38 × 10-4,pK_a = 3.86)

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Quizplus · Accepted Answer

A good buffer should have a pKa value close to the target pH, which is 5.0 in this case. The closer the pKa value to the pH, the better the buffer capacity. Among the options given, acetic acid has the closest pKa value to 5.0 (pKa = 4.76), making it the best choice for a buffer at pH 5.0.

Which of the Following Weak Acids Would Make the Best