Saved Bookmarks
| 1. |
Bromophenol blue is anindicatorwith a valueof K_(a) = 5.84 xx10^(-5) . At whatworkas anindicator ?Alsoreportthe% of thisindicatorin its basicfor at a pH of 4.84 . |
|
Answer» Solution :`HBPh hArrH^(+) + BPh^(-)` `K_(a) = ([H^(+)][BPh^(-)])/([HBPh]) , `when`BPh^(-)` = HBPh ,indicatorwill work . THUS ` [H^(+)] = 5.84 xx10^(-5)` ` :. pH = 4.2336` ALSOIF pH= 4.84 or `[H^(+]= 1.44 xx10^(-5) ` , then `K_(a) = ([H^(+)] [BPh^(-)])/([HBPh])` or `5.84 xx10^(-5) = (1.44 xx10^(-5)CALPHA)/(C(1-alpha))` `alpha = 0.8 ` or 80 % |
|