What happens when
i. Hydrogen sulhide is bubbled through an aqueous solution of sulphur dioxide .
ii . Aqueous ammonia in added dropwise to a solution of copper sulphate till it is in excess
iii Tin in treated with concentrated nitric acid d
iv `CrCI_(3)` solution is treated with sodium hydroxide and then with hydrogen peroxide
v. `Pb_(3)O_(4)` is treated with nitric acid

Explanation

Sulphate is precipitate
`SO_(2) + 2H_(2)S rarr 3S + 2H_(2)O`
ii. Ammonia gives deep blue colour with copper sulphide due to the formation of a complex
`CaSO_(4) + 2NH_(4)OH rarr Cu(OH)_(2) + (NH_(4))_(2)SO_(4)`
`Cu(OH)_(2) + 2NH_(4)OH +(NH_(4))_(2)SO_(4) rarr underset(blue)([Ca(NH_(3))_(4)])SO_(4) + 4H_(2)O`
iii. Metastamic acid id formed
`Sn + 3HNO_(3) (conc.) rarr H_(2)SnO_(3) + 4NO_(2) + H_(2)O`
iv . A yellow solution of sodium chromate is produced
`H_(2)O_(2) rarr H_(2)O + O`
`2CrCI_(3) + 10NaOH + 3[O] rarr 2NaCrO_(4) + 6 NaCI + 3H_(2)O`
Lead dioxide is precipitate
`Pb_(3)O_(4) +_ 4HNO_(3) rarr 2Pb(NO_(3))_(2) 2H_(2)O + PbO_(2)`