Stock $1$ was prepared by dissolving a Sn sample in $1\mathrm{.}0000$ L of nitric acid.

Stock $2$ was prepared by diluting a $28\mathrm{.}11$ mL aliquot of the stock $1$ to $250\mathrm{.}0$ mL$.$

Stock $3$ was prepared by diluting a $22\mathrm{.}76$ mL aliquot of stock $2$ to $200\mathrm{.}0$ mL$.$

Stock $4$ was prepared by diluting $10\mathrm{.}8$ mL of stock $3$ to $100\mathrm{.}0$ mL$.$

Stock $4$ was analyzed to contain $2\mathrm{.}204$ mg$/$L$.$

What is the concentration of Sn in mg$/$L in Stock $3.$