The volume of the buffer to be added will be 0.95 mL.
<h3>Dilution problem</h3>
Recall the general dilution equation:
M1V1 = M2V2, where M1 and M1 are the initial and final concentrations, and V1 and V2 are the initial and final volumes.
In this case,
M1 = 400.0 u/mL, M2 = 20.0 u/mL, V2 = 1 mL
Thus, V1 = M2V2/M1 = 20 x 1/400 = 0.05 mL
This means that 0.05 mL of the 400.0 u/mL is required. Then, a buffer will be added to the 1 mL mark. The volume of the buffer to be added can be calculated as;
Volume = 1 - 0.05 = 0.95 mL
More on dilution problems can be found here: brainly.com/question/14083644
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