A chemistry graduate student is given 125. mL of a 1.30 M propanoic acid (HC2H, Co2) solution. Propanoic acd is a weak acid with K - 1.3 10-5. what mass of KC2H CO2 should the student dissolve in the HC2H, CO2 solution to turn it into a buffer with pH 5.02?

Answer : The  mass of is, 24.5 grams

Explanation : Given,

pH = 5.02

Concentration of = 1.30 M

Volume of solution = 125 mL = 0.125 L

First we have to calculate the value of .

The expression used for the calculation of is,

Now put the value of in this expression, we get:

Now we have to calculate the concentration of

Using Henderson Hesselbach equation :

Now put all the given values in this expression, we get:

Now we have to calculate the moles of

Now we have to calculate the mass of

Molar mass of = 112 g/mol

Thus, the mass of is, 24.5 grams

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