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Explain the Mechanism or working of a basic buffer. |
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Answer» Solution :Consider a basic buffer solution, `NH_(4)OHhArrNH_(4)^(+)+OH^(-),NH_(4)Cl toNH_(4)^(+)+Cl^(-)` Here, ammonium hydroxide is a weak electrolyte, in solution there exist equilibrium between it is ions and molecules, whereas ammonium chloride completely DISSOCIATES into its ions. Therefore, this basic buffer solution contains a large number of `NH_(4)^(+)` ions followed by `Cl^(-),OH^(-)andNH_(4)OH`. Case (i) When a base is added to this solution: `OH^(-)` ion of the base combines with the `NH_(4)^(+)` ion of the buffer solution and MAINTAINS equilibrium forming ammonium hydroxide. `NH_(4)^(+)+OH^(-)hArrNH_(4)OH`, As a result POH remains constant Case (ii) When an acid is added to this solution : `H^(+)` ion of the acid combines with the `OH^(-)` ion of the buffer solution and forms a water molecule. `H^(+)+OH^(-)toH_(2)O` As a result pOH remains constant. |
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