Which from following functional groups is at the lowest order to decide principal functional group in polyfunctional compound?

Calculate the $$\mathrm{E}_{\text {cell }}$$ for $$\mathrm{Zn}_{(\mathrm{s})}\left|\mathrm{Zn}_{(0.1 \mathrm{M})}^{++}\right|\left|\mathrm{Cr}_{(0.1 \mathrm{M})}^{+++}\right| \mathrm{Cr}_{(\mathrm{s})}$$ at $$25^{\circ} \mathrm{C}$$ if $$\mathrm{E}_{\text {cell }}^{\circ}$$ is $$0.02 \mathrm{~V}$$

Which from following formulae is of galena?

What is the solubility of $$\mathrm{AgCl}_{(\mathrm{s})}$$ if its solubility product is $$1.6 \times 10^{-10}$$ ?