The oxidation state of sulphur in $\mathrm{H}_2 \mathrm{S}_2 \mathrm{O}_7$ is

The reaction in which 2 molecules of chlorobenzene reacts with metallic sodium in presence of dry ether forming diphenyl is an example of,

The percentage of unoccupied volume in simple cubic cell is

Isobutylene on hydroboration followed by oxidation with hydrogen peroxide in presence of base yields