a
a
No. of moles of \(\operatorname{CoCl}_{3}-6 \mathrm{NH}_{3}=(2.675) /(267.5)=0.01\)

No. of moles of \(\mathrm{AgCl}=(4.78) /(143.5)=0.03\)

since \(0.01\;moles\) of the complex \(\mathrm{CoCl}_{3} \cdot 6 \mathrm{NH}_{3}\) gives \(0.03\; moles\) of \(AgCl\) on treatment with \(AgNO_{3}\) , it implies that \(3\) chloride ions are ionisable, in the complex.

Thus, the formula of the complex is

\(\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}\)