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pH缓冲溶液在化学化工等许多领域都有着广泛的用途。除了对酸碱的缓冲作用外,它的另一重要性质是当被适当稀释时能保持pH不发生明显变化。对于这一问题报道甚少。J.N.Butler根据 K_a=[H~+](C_A-[OH~-]+[H~+]/(C_(HA)+[OH~-]-[H~+] (1)中的[OH~-]与C_A或[H~+]与C_(H_A)相比是否可以忽略来判断pH是否发生了变化。这需要解高次方程或使用逼近法。对于HA~-类缓冲溶液的稀释问题的讨论尚未见报道。本文推导了缓冲溶液在稀释过程中不发生pH改变的判别式。并对HA—A~-型缓冲溶液进行了实验验证,与理论值相符。
pH buffer solution has many applications in many fields such as chemical engineering. In addition to its acid-base buffering effect, another important property of it is to keep the pH unchanged when properly diluted. Very few reports on this issue. JNButler calculates the number of peaks in the range of [OH ~ +] in K_a = [H ~ +] (C_A- [OH ~ -] + [H ~ +] / (C_ (HA) + [OH ~ -] - [H ~ +] -] and C_A or [H ~ +] and C_ (H_A) is negligible compared to determine whether the pH has changed, which need to solve the high order equation or the use of approximation method for dilution HA ~ - buffer solution The discussion has not been reported yet.This paper derives the discriminant of the pH-free buffer solution during the dilution process, and the HA-A ~ -type buffer solution is verified by experiments, which is consistent with the theoretical value.