A buffer solution is prepared by mixing 0.20 mol of ethanoic acid with 0.20 mol of sodium ethanoate in 1 dm³ of solution. Given that the $ ext{p}K_a$ of ethanoic acid is 4.76, what is the pH of the buffer?

Question

A buffer solution is prepared by mixing 0.20 mol of ethanoic acid with 0.20 mol of sodium ethanoate in 1 dm³ of solution. Given that the $	ext{p}K_a$ of ethanoic acid is 4.76, what is the pH of the buffer?

Accepted Answer

4.76. Using the Henderson–Hasselbalch equation: pH = pKa + log([A⁻]/[HA]) = 4.76 + log(0.20/0.20) = 4.76 + log(1) = 4.76 + 0 = 4.76. When the concentrations of the weak acid and its conjugate base are equal, the pH equals the pKa of the acid.

Answer

A) 3.76

Answer

B) 4.76

Answer

C) 5.76

Answer

D) 7.00

A buffer solution is prepared by mixing 0.20 mol of ethanoic acid with 0.20 mol of sodium ethanoate in 1 dm³ of solution. Given that the $\text{p}K_a$ of ethanoic acid is 4.76, what is the pH of the buffer?

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