Saved Bookmarks
| 1. |
The Ka of propionic acid is 1.34 xx 10^(-5). What is the pH of a solution containing 0.5 M propionic acid and 0.5 M sodium proportionate ? What happens to the pH of the solution when volume is doubled by adding water ? |
|
Answer» Solution :`Ka" of propionic ACID "=1.34xx10^(-5)` `THEREFORE""pK_(a)=-logK_(a)=-log(1.34xx10^(-5))` `=4.87` By Herderson - Hasselbalch equation `pH=pK_(a)+log.(["salt"])/(["acid"])` `=4.87+log""(0.5)/(0.5)` `pH=4.87` 87 Alternative solution : The DISSOCIATION EQUILIBRIUM of propionic acid will be `K_(a)=([C_(2)H_(5)COO^(-)][H^(+)])/([C_(2)H_(5)COOH])=(0.5xx[H^(+)])/(0.5)` `=[H^(+)]` `therefore""pH=-log[H^(-)]` `=-logK_(a)=-log(1.34xx10^(-5))` `therefore pH=4.87` |
|