The conductivity of a solution of complex with formula $$\mathrm{CoCl}_{3}\left(\mathrm{NH}_{3}\right)_{4}$$ corresponds to 1 : 1 electrolyte, then the primary valency of central metal ion is __________.

In the titration of $$\mathrm{KMnO}_{4}$$ and oxalic acid in acidic medium, the change in oxidation number of carbon at the end point is ___________.

Optical activity of an enantiomeric mixture is $$+12.6^{\circ}$$ and the specific rotation of $$(+)$$ isomer is $$+30^{\circ}$$. The optical purity is __________$$\%$$.

In the following reaction

The $$\%$$ yield for reaction I is $$60 \%$$ and that of reaction II is $$50 \%$$. The overall yield of the complete reaction is __________ $$\%$$. [nearest integer]