《絡合滴定法》ppt課件 (2)-文庫吧
2025-04-18 04:17 本頁面
【正文】 K2K3= 1 Ka4 K4= = ?4=K1K2K3K4= 1 Ka3 K5= = ?5=K1K2..K5= 1 Ka2 K6= = 10 ?6=K1K2..K6 = 1 Ka1 EDTA的有關(guān)常數(shù) 常數(shù) β6 β5 β4 β3 β2 β1 累積 常數(shù) K6 K5 K4 K3 K2 K1 逐級 常數(shù) Ka6 Ka5 Ka4 Ka3 Ka2 Ka1 離解 M + Y = MY 主反應 副反應 OH L H+ N H+ OH MOH MHY MOHY NY HY M(OH)n ● ● ● ● ● ● ML MLn H6Y ● ● ● ● ● ● ● ● ● ● ● ● ?M ?Y ?MY 副反應系數(shù) :為未參加主反應組分的濃度 [X?] 與平衡濃度 [X]的比值，用 ?表示。 [M?] ?M= [M] [Y?] ?Y= [Y] [MY?] ?MY= [MY] 1 副反應系數(shù) M + Y = MY 主反應 副反應 OH L H+ N H+ OH MOH MHY MOHY NY HY M(OH)n ● ● ● ● ● ● ML MLn H6Y ● ● ● ● ● ● ● ● ● ● ● ● [M?] [Y?] [MY?] a 絡合劑的副反應系數(shù) ?Y: ?Y(H)： 酸效應系數(shù) ?Y(N)： 共存離子效應系數(shù) [Y?] ?Y= [Y] H+ N NY HY H6Y ● ● ● ?Y M + Y = MY 1 ?Y 酸效應系數(shù) ?Y(H)： [Y?] ?Y(H)= = = [Y] =(1+?1[H+]+?2[H+]2+…+ ?6[H+]6) [Y] [Y]+[HY]+[H2Y]+…+[H 6Y] [Y] [Y]+[Y][H+]?1+[Y][H+]2?2+…+[Y][H +]6?6 = ?Y(H) ≥1 [Y?] ?Y(H) [Y] = 共存離子效應系數(shù) ?Y(N) [Y?] ?Y(N)= = = 1+ KNY[N] [Y] [Y] [Y]+[NY] [Y?] ?Y(N)= = = 1+KN1Y[N1]+KN2Y[N2]+…+ KNnY[Nn] =?Y(N1)+?Y(N2)+…+ ?Y(Nn)(n1) [Y] [Y] [Y]+[N1Y]+[N2Y]+…+[N nY] 多種共存離子 Y的總副反應系數(shù) ?Y = ?Y(H) + ?Y(N) 1 ?Y= = [Y]+[HY]+[H2Y]+ +[NY] [Y] [Y?] [Y] b 金屬離子的副反應系數(shù) ?M ?M(OH) =1 +?1[OH]+ ?2[OH]2+ …+ ?n[OH]n ?M(L) =1+?1[L] +?2[L]2+…+ ?n[L]n M + Y = MY OH L MOH M(OH)n ● ● ● ML MLn ● ● ● ?M 多種絡合劑共存 ?M(L) =1+?1[L] +?2[L]2+…+ ?n[L]n ? M = ? M(L1)+ ? M(L2) +…+ ? M(Ln)(n1) c 絡合物的副反應系數(shù) ? MY 酸性較強 ?MY(H)= 1+ KMHY [H+] 堿性較強 ?MY(OH)= 1+ KM(OH)Y [OH] M + Y = MY H+ OH MHY MOHY ?MY 計算： pH=、 lg ?ZnY(H), KZnHY= pH=, αZnY(H)=1++=2 , lgαZnY(H)= pH=, αZnY(H)=1++=1, lgαZnY(H)= 0 lg K?MY = lgKMY lg?M lg?Y + lg ?MY ≈ lgKMY lg?M lg?Y = lgKMY lg(? M(A1)+? M(A2) +…+ ? M(An)(n1)) lg (?Y(H) + ?Y(N) 1) K?MY = =KMY [M
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