The final volume of buffer solution must be 100.00 mL and the final concentration of the weak acid must be 0.100 M. Based on this information, what mass of solid conjugate base should the student weigh out to make the buffer solution with a pH of 2.00?

The mass of base required is 3.87 g.

Explanation:

The given data is as follows.

       pH of buffer = 2.0,         volume of the solution (V) = 100 mL,

  molarity of HA, [HA] = 0.1 M,      

Now, we will calculate the value of as follows.

                    =  

                    = 1.92

According to Henderson equation,

         pH =

        2.0 =

      = 0.12 M

 Moles of base =

                         = 0.012 mol

Hence, mass of the base will be calculated as follows.

               = 3.87 g

Hence, the mass of base required is 3.87 g.

the answer would be c