Saved Bookmarks
| 1. |
Explain Mechanism or working of an acid buffer: |
|
Answer» Solution :Consider the acidic buffer mixture, `CH_(3)COOHhArrCH_(3)COO^(-)+H^(+),CH_(3)COONatoCH_(3)COO^(-)+Na^(+)` Here, acetic acid is a WEAK electrolyte and its solution there exists equilibrium between its ions and molecules, whereas SODIUM acetate completely dissociates into its ions. Therefore, the buffer mixture contains large number of `CH_(3)COO^(-)` ions followed by `Na^(+),H^(+),CH_(3)COOH`. Case (i) When an acid is added to this solution: `H^(+)` ion of the acid COMBINES with `CH_(3)COO^(-)` ion in the buffer solution and makes equilibrium forming acetic acid. `CH_(3)COO^(-)+H^(+)hArrCH_(3)COOH` As a result pH remains constant Case (ii) When a BASE is added to this solution: `OH^(-)` ion of the base combines with `H^(+)` ion in the buffer solution to form a water MOLECULE `H^(+)+OH^(-)toH_(2)O` As a result pH remains constant. |
|