On treatment of 100mL of 0.1M Solution of ${\mathrm{CoCl}}_3.6{\mathrm{H}}_2\mathrm{O}$with excess of ${\mathrm{AgNO}}_3, 1.2\times {10}^{22}$ions are precipitated. The complex is

$0.1=\mathrm{n}\times \frac{1000}{100}\Rightarrow \mathrm{n}=0.01\mathrm{moles}$

$\mathrm{no}.\mathrm{of}\mathrm{moles}=\frac{\mathrm{given}\mathrm{no}.\mathrm{of}\mathrm{ions}}{\mathrm{Avagadom}\mathrm{no}.}$

$=\frac{1.2\times {10}^{22}}{6.023\times {10}^{23}}$

= 0.02 mol

$\therefore$Hence two chloride ions can be precipitated