Explanation:
According to the law of dilution,
    [tex]M_{1}V_{1} = M_{2}V_{2}[/tex]
The given data is as follows.
  [tex]M_{1}[/tex] = 0.4782,   [tex]V_{1}[/tex] = ?
  [tex]M_{2}[/tex] = 0.025 ,   [tex]V_{2}[/tex] = 250 mL
Hence, we will calculate the value of [tex]V_{1}[/tex] as follows.
       [tex]V_{1} = \frac{M_{2} \times V_{2}}{M_{1}}[/tex]
             = [tex]\frac{0.025 \times 250}{0.4782}[/tex]
             = 13.07
Thus, we can conclude that we need 13.07 mL 0.4782 M sodium thiosulfate solution using pipette.
