Correct solubility order of $$\mathrm{AgF}, \mathrm{AgCl}, \mathrm{AgBr}, \mathrm{AgI}$$ in water is

What will be the change in acidity if

(i) $$\mathrm{CuSO}_4$$ is added in saturated $$(\mathrm{NH}_4)_2 \mathrm{SO}_4$$ solution

(ii) $$\mathrm{SbF}_5$$ is added in anhydrous $$\mathrm{HF}$$

Number of moles of ions produced by complete dissociation of one mole of Mohr's salt in water is

$$\mathrm{pH}$$ of $$10^{-8}(\mathrm{M}) \mathrm{~HCl}$$ solution is