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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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.
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.
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.
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