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The ionization constant of phenol is `1.0xx10^(-10)`. What is the concentration of phenolate ion in `0.05 M` solution of phenol? What will be its degree of ionization if the solution is also `0.01 M` in sodium phenolate? |
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Answer» i. `{:(C_(6)H_(5)OH,hArr,C_(6)H_(5)O^(Θ),+,H^(o+)),(C(1-alpha),,Calpha,,Calpha):}` `K_(a)` of phenol`=1.0xx10^(-10) (Phenol is a W_(A))` `:. alpha=sqrt(K_(a)/C)=sqrt((1.0xx10^(-10))/0.05)=sqrt((10^(-10)xx100)/5)` `sqrt(10^(-10)xx20)=4.47xx10^(-5)M` ii. Phenate ion, `[C_(6)H_(5)O^(Θ)]=Calpha` `=(0.05xx4.47xx10^(-5))` `=2.2xx19^(-6)M` iii. `pH=- log(2.2xx10^(-6))M=5.65` iv. When the concentration of phenate is `0.01 M` (salt) and concentration of phenol (acid) is `0.05 M`. It forms acidic buffer. `:. pH=pK_(a)+log [("Salt")/("Acid")]` `=10+log(0.01/0.05)` `=10-0.7=9.3` |
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