The volume (in mL ) of $0.1 \mathrm{M} \mathrm{AgNO}_3$ required for complete precipitation of chloride ions present in 20 mL of 0.01 M solution of $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_5 \mathrm{Cl}_1\right] \mathrm{Cl}_2$ as silver chloride is $\_\_\_\_$ .
