大学化学 >> 2021, Vol. 36 >> Issue (6): 2008011.doi: 10.3866/PKU.DXHX202008011

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一元弱酸HA和HB混合溶液的pH计算

何大卫, 王海水()   

  • 收稿日期:2020-08-04 录用日期:2020-09-01 发布日期:2020-10-09
  • 通讯作者: 王海水 E-mail:wanghsh@scut.edu.cn
  • 作者简介:王海水, Email: wanghsh@scut.edu.cn
  • 基金资助:
    国家自然科学基金(21773072)

The pH Calculation of the Mixed Weak Acids of HA and HB Solutions

Dawei He, Haishui Wang()   

  • Received:2020-08-04 Accepted:2020-09-01 Published:2020-10-09
  • Contact: Haishui Wang E-mail:wanghsh@scut.edu.cn

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摘要：

对于一元弱酸HA或HB的纯溶液，如果cHAKHA >10Kw和cHBKHB >10Kw，则可用一元弱酸溶液中H+浓度的近似式分别得到纯HA溶液的[H+]HA和纯HB溶液的[H+]HB。本文研究了HA和HB混合酸溶液近似氢离子浓度[H+]p与[H+]HA和[H+]HB的关系。研究表明，如果允许[H+]p与混合酸溶液准确氢离子浓度[H+]T有±5%误差（±0.02 pH），则本文提出的新公式[H+]p满足近似计算要求。使用[H+]p式条件：cHA ≥2KHA和cHB ≥2KHB。[H+]p近似式简单，适用浓度范围宽，为一元酸混合溶液pH计算带来便利。

关键词: 一元弱酸, 混合溶液, pH, 近似式

Abstract:

A novel approximate formula [H+]p is proposed to obtain the pH of the mixed HA and HB solutions, where[H+]HA and[H+]HB are the estimated values of[H+] for HA solution and HB solution, respectively. If cHA ≥ 2KHAand cHB ≥ 2KHB, [H+]p formula will work very well. The novel approximation formula is simple, easy to remember, and can be widely used to calculate the pH of the mixed monoprotic weak acid HA and HB solutions.

Key words: Monoprotic weak acid, Mixed solution, pH, Approximation formula