Abstract The amphiprotic NaHA can be divided into acidic and alkaline substances. If NaHA is acidic, its solution has a pH range of (pKa1+pKa2)/2<pH<7.00. If NaHA is alkaline, the pH range of its solution covers 7.00<pH<(pKa1+pKa2)/2. Based on the acid-base properties of NaHA solution, ignoring the minor components, the approximate formula of pH for acidic or alkaline solution is obtained, respectively. The new approximate formula derived in this paper has the following characteristics: It can be used in very dilute solution(1.0×10-5 mol·L-1), its physical meaning is clear, and the approximate result satisfies the requirement of ±5% error.
ABULIMITI Alafate, WANG Hai-Shui. New Approximate Formula for pH Calculation of Amphiprotic NaHA Solution[J]. Chinese Journal of Chemical Education, 2022, 43(8): 122-125.
