Question

"What volume of reduced soy sauce (575 mg Na/15 mL) would be predicted to require 25.00 mL of 1.0 M AgNO3 for titration assuming all the sodium is derived from NaCl? A.W. Na= 23

Answer 1

I would convert 575 mg Na to mmols Na. mmoles Na = mmols NaCl = 575 mg Na/23 = ??
Titrate with AgNO3 = 0.1M x 25.00 mL = 2.50 mmols AgNO3 which will equal 2.50 mmoles NaCl. (You should write the NaCl + AgNO3 equation to confirm that.)

You have a soy sauce that is 25.00 mmols/15 mL and you want to know how many mL will be required to equal 2.50 mmoles.
(mmoles NaCl/15 mL)* X mL = 2.50 mmoles.
Solve for X mL.