How many grams of sodium fluoride should be added to 300. ml of 0.0310 m of hydrofluoric acid to produce a buffer solution with a ph of 2.60?

Answer : The mass of sodium fluoride added should be 0.105 grams.

Explanation : Given,

The dissociation constant for HF =

Concentration of HF (weak acid)= 0.0310 M

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 NaF.

Using Henderson Hesselbach equation :

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

Now we have to calculate the moles of NaF.

Now we have to calculate the mass of NaF.

Therefore, the mass of sodium fluoride added should be 0.105 grams.