Apurified protein is in a hepes (n-(2-hydroxyethyl)piperazine-n-(2- ethanesulfonic acid)) buffer at ph 7 with 800 mm nacl. a sample (1 ml) of the protein solution is placed in a tube made of dialysis membrane and dialyzed against 1.0 l of the same hepes buffer with 0 mm nacl. small molecules and ions (such as na, cl, and hepes) can diffuse across the dialysis membrane, but the protein cannot.

a) once the dialysis has come to equilibrium, what is the concentration of nacl in the protein sample? assume no volume changes occur in the sample during the dialysis.
b) if the original 1 ml sample were dialyzed twice, successively, against 100 ml of the same hepes buffer with 0 mm nacl, what would be the final nacl concentration in the sample?