Question

If `"100 mL"` of `"0.01 mol/L"` tetraaquadichlorochromium(III) chloride reacts with excess silver nitrate, how many mols of silver chloride get produced?

Answer 1

This is just a double replacement reaction in disguise. The balanced reaction has all coefficients of `1`:

`"AgNO"_3(aq) + [stackrel(color(blue)(+3))("Cr")("H"_2"O")_4stackrel(color(blue)(-1))("Cl"_2)]stackrel(color(blue)(-1))("Cl")(aq) -> "AgCl"(s) + ["Cr"("H"_2"O")_4"Cl"_2]"NO"_3(aq)`

Only the ion in the outer coordination sphere gets displaced here; the complex coordinated to the outer `"Cl"^(-)` has an overall charge of `+1`.

By the stoichiometry of the reaction, the mols of `"AgCl"` are equal to the mols of `"Cl"^(-)` from the limiting reagent, which is implicitly declared to be the transition metal complex, `["Cr"("H"_2"O")_4"Cl"_2]"Cl"`.

`color(blue)(n_(AgCl) = n_(["Cr"("H"_2"O")_4"Cl"_2]"Cl"))`

`= "0.01 mols"/cancel"L" xx 100.00 xx 10^(-3) cancel"L"`

`=` `color(blue)("0.001 mols AgCl")`