Among the following, total number of meta directing functional groups is (Integer based)

$$-\mathrm{OCH}_3,-\mathrm{NO}_2,-\mathrm{CN},-\mathrm{CH}_3-\mathrm{NHCOCH}_3, -\mathrm{COR},-\mathrm{OH},-\mathrm{COOH},-\mathrm{Cl}$$

The number of electrons present in all the completely filled subshells having $$\mathrm{n}=4$$ and $$\mathrm{s}=+\frac{1}{2}$$ is _______.

(Where $$\mathrm{n}=$$ principal quantum number and $$\mathrm{s}=$$ spin quantum number)

Sum of bond order of CO and NO$$^+$$ is ________.

From the given list, the number of compounds with +4 oxidation state of Sulphur ________.

$$\mathrm{SO}_3, \mathrm{H}_2 \mathrm{SO}_3, \mathrm{SOCl}_2, \mathrm{SF}_4, \mathrm{BaSO}_4, \mathrm{H}_2 \mathrm{S}_2 \mathrm{O}_7 $$