CHANGE IN pH OF AN ACIDIC AND BASIC BUFFER

CALCULATION OF PH OF ACIDIC AND BASIC BUFFER SOLUTION (HENDERSON-HASSELBALCH EQUATION)

Higher the amount of acid or base used to product a deinite change of pH in a buffer solution, higher will be its buffe capacity. Buffer capcity of solution is maximum under the following conditions [Salt] = [Acid](in acid buffer) [Salt] = [Base] (in base capacity] pH of buffer solution lies inthe range given below pH = pH_(a) +-1 In other words,any buffer solution can be used as buffer up to two pH units only, depending upon the value of pK_(a) or pK_(b) . A buffer is said to be efficient when pH = pK_(a) or pOH = pK_(b) Acifity of BF_(3) can be explained on the basis of which of the following concepts

The pH of basic buffer mixtures is given by : pH=pK_(a)+log((["Base"])/(["Salt"])) , whereas pH of acidic buffer mixtures is given by: pH= pK_(a)+log((["Salt"])/(["Acid"])) . Addition of little acid or base although shows no appreciable change for all practical purpose, but since the ratio (["Base"])/(["Salt"]) or (["Salt"])/(["Acid"]) change, a slight decrease or increase in pH results in. A weak acid HA after treatment with 12 mL of 0.1M strong base BOH has a pH=5 . At end point, the volume of same base required is 26.6mL K_(a) of acid is:

Buffer Action Of Acidic And Basic Buffer

Basic Buffer || pH Determination Formula || Buffer Action OF Acidic Buffer || Solved Numerical Class illustration and Buffer Capacity

The pH of basic buffer mixtures is given by : pH=pK_(a)+log((["Base"])/(["Salt"])) , whereas pH of acidic buffer mixtures is given by: pH= pK_(a)+log((["Salt"])/(["Acid"])) . Addition of little acid or base although shows no appreciable change for all practical purpose, but since the ratio (["Base"])/(["Salt"]) or (["Salt"])/(["Acid"]) change, a slight decrease or increase in pH results in. Mole of HCI required to prepare a buffer solution of pH=8.5 with 0.1 mole of NaCN in one litre solution is: (pK_(a) for CN^(-)=4.61)

The solution which consumes [H^(+)] or [OH^(-)] or both simultaneously from externally added base in order to give negligible change in pH , is known as buffer solution. In general, the solution resists the change in pH. Buffer solution does not mean that there does not occur a pH change in pH. Buffer solution des not mean that there does not occur a pH change at all. It implies the pH change occurs but in neglibible amount. There are two types of buffer (i) Acidic buffer: it is a mixture of weak acid and its salt acid strong base. (ii) Basic buffer : It is a mixture of weak base and its salt with strong acid. pH of 0.01 M (NH_(4))_(2)SO_(4) and 0.02 M NH_(4)OH buffer ( pK_(a) of NH_(4^(+)) = 9.26) is

Assertion : Buffer solutions are those which resist change in pH value on the addition of a small amount of acid or a base to it. Reason: Mixture of NH_4OH and NH_4 Cl acts as basic buffer.