Dimethyl glyoxime forms a coloured complex with

On treatment of $100 \ mL$ of $0.1 \ M$ solution of $CoCl_3 \cdot 6H_2O$ with excess $AgNO_3$,$1.2 \times 10^{22}$ ions are precipitated. The complex is:

The molar ionic conductances of the octahedral complexes:
$(I)$ $PtCl_4 \cdot 5NH_3$
$(II)$ $PtCl_4 \cdot 4NH_3$
$(III)$ $PtCl_4 \cdot 3NH_3$
$(IV)$ $PtCl_4 \cdot 2NH_3$
Follow the order $-$

Select the most stable complex.

Which of the following complexes has the highest $C-O$ bond length?

Transition elements in lower oxidation states act as Lewis acid because