What is the pH at the stoichiometric point for the titration

zpvic2022-10-04 11:39:541条回答

What is the pH at the stoichiometric point for the titration of 0.1M CH3COOH with 0.1M Ca(OH)2?The value of acetic acid,Ka=1.8x10^-5.
options:
A=9.56;
B=8.88;
C=9.26;
D=7.00;
E=8.79.

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张祖全共回答了25个问题 | 采纳率92%: Ca(OH)2 + 2CH3COOH = Ca^2+ + 2CH3COO^- +2H2O
stoichiometric point ：CH3COO^- 0.1/1.5 = 0.06667mol/L ；Kb=Kw/Ka=10^(-9.25)
pOH=1/2(p0.06667+pKb)=5.21
pH =14.00 - 5.21=8.79; 1年前

What is the pH at the stoichiometric point for the titration What is the pH at the stoichiometric point for the titration of 0.1M CH3COOH with 0.1M Ca(OH)2?The value of acetic acid,Ka=1.8x10^-5. options: A=9.56; B=8.88; C=9.26; D=7.00; E=8.79. janachen1年前1: espdazzle 共回答了12个问题 | 采纳率100%

the stoichiometric point 就是化学计量点
也就是乙酸与氢氧化钙刚好完全反应
Ca(OH)2+2HAc=Ca(Ac)2+2H2O
2份体积的0.1M的HAc与1份体积的0.1M的Ca(OH)2反应
最终溶液也就是乙酸钙的溶液
[Ac-]=0.1*2/3=0.067mol/L

AC-+H2O=可逆=HAc+OH-
Kb=Kw/Ka=5.56*10^-10
Kb=[OH-][HAC]/[AC-]
设[OH-]=[HAc]=xmol/L,则[Ac-]=0.067-xmol/L,代入得
x^2/(0.067-x)=5.56*10^-10
解得x=6.1*10^-6
[OH-]=6.1*10^-6mol/L
[H+]=1.64*10^-9mol/L
PH=9-lg1.64=9-0.21=8.79
选E

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What is the pH at the stoichiometric point for the titration

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