A 30.0-mL sample of 0.165 M propanoic acid is titrated with 0.300 M KOH. Calculate the pH at each volume of added base: 5 mL.

검증된 단계별 안내

Determine the initial moles of propanoic acid (C2H5COOH) using the formula: \( \text{moles} = \text{concentration} \times \text{volume} \).

Calculate the moles of KOH added using the formula: \( \text{moles} = \text{concentration} \times \text{volume} \).

Determine the moles of propanoic acid that react with KOH, considering the stoichiometry of the reaction: \( \text{C2H5COOH} + \text{KOH} \rightarrow \text{C2H5COOK} + \text{H2O} \).

Calculate the moles of propanoic acid and its conjugate base (propanoate ion, C2H5COO-) remaining after the reaction.

Use the Henderson-Hasselbalch equation to find the pH: \( \text{pH} = \text{pKa} + \log \left( \frac{[\text{C2H5COO-}]}{[\text{C2H5COOH}]} \right) \), where \( \text{pKa} \) is the acid dissociation constant of propanoic acid.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.

영상 길이:

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Acid-Base Titration

An acid-base titration is a quantitative analytical method used to determine the concentration of an acid or base in a solution. In this process, a solution of known concentration (the titrant) is added to a solution of unknown concentration until the reaction reaches its equivalence point, where the amount of acid equals the amount of base. The pH changes during the titration can be monitored to determine the endpoint.

Weak Acid and Strong Base Reaction

In this titration, propanoic acid (a weak acid) reacts with potassium hydroxide (a strong base). The weak acid does not fully dissociate in solution, which affects the pH at various points during the titration. The resulting solution will have a pH that is influenced by the remaining weak acid and the produced salt, as well as the strong base added.

Henderson-Hasselbalch Equation

The Henderson-Hasselbalch equation is a formula used to calculate the pH of a buffer solution. It relates the pH to the pKa of the weak acid and the ratio of the concentrations of the conjugate base to the weak acid. This equation is particularly useful in titration scenarios to determine the pH at points before, at, and after the equivalence point, especially when dealing with weak acids and their conjugate bases.