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How to prepare sodium acetate buffer with ph=5
PH=PKa+lg[C(NaAc)/C(HAc)] prepared with acetic acid and sodium acetate (where C(HAc) refers to the concentration of acetic acid, C(NaAc) refers to the concentration of sodium acetate, and Ka is the dissociation constant of acetic acid = 1.8 * 10 -5 (65448

Generally, C(HAc)=0. 1mol/L, or C(HAc)=0.2mol/L, etc. If C(HAc)= 0. 1 mol/L, then c (NAAC) = 0.56 mol/L.

The weighed solid mass of sodium acetate is 82 * 0.56 = 46g. The volume of glacial acetic acid is 0.1*1000/17.5 = 5.7 ml. Add the weighed sodium acetate and appropriate glacial acetic acid into 1000mL water to dissolve and stir evenly.

Extended data:

Preparation of buffer solution

In order to prepare a buffer solution with a certain pH value, firstly, a weak acid with pKaφ as close as possible to the pH value of the buffer solution to be prepared is selected, and then the concentration ratio of acid and alkali is calculated, so that the required buffer solution can be prepared.

The above mainly takes the buffer solution composed of weak acid and its salts as an example to illustrate its action principle, pH value calculation and preparation method. The same method can also be used for buffer solution composed of weak base and its salt.

Buffer solution is widely used for material separation and composition analysis. For example, when Mg2+ ions are recognized, the following reaction can be used:

White magnesium ammonium phosphate precipitate is soluble in acid, so the reaction needs to be carried out in alkaline solution. However, if the alkalinity is too strong, white Mg(OH)2 precipitate may be generated, so it is necessary to control the pH value of the reaction within a certain range. Therefore, the above reaction is carried out by using a buffer solution composed of NH3·H2O and NH4Cl to maintain the pH value of the solution.

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