Answer:
The easiest way to make these solutions is preparing serial dilutions with dilution factor of 10.
Explanation:
In chemistry, a dilution is the way to reducing the concentration of a chemical adding more solvent.
To prepare the first 0,100 M NaCl from 1,00 M NaCl:
You must take an aliquot of 25,0 mL of 1,00 M NaCl and dilute until 250,0 mL. Thus, the concentration will decrease ten times until the expected concentration. The dilution factor is 10.
To prepare the second 0,0100 M of NaCl:
From 0,100 M NaCl take an aliquot of 25 mL an dilute until 250,0 mL. Thus, the concentration will decrease ten times.
So, to prepare each solution you must take the last one and dilute it in a dilution factor of 10.
I hope it helps!