An aqueous blue coloursolutionof atransitionmetal sulphate reacts with H_(2)S in acidicmedium to give a blackprecipitate A which is insolution in warm aqueoussolution of KOH .The bluesolutionon tretmentwith KJ inweakly acidic mediumturns yellowand producesa whiteprecipitate B identify the transitionmetalion write thechemicalreactioninvolved in theformation of A and B

An aqueous blue coloursolutionof atransitionmetal sulphate reacts with

1.	An aqueous blue coloursolutionof atransitionmetal sulphate reacts with H_(2)S in acidicmedium to give a blackprecipitate A which is insolution in warm aqueoussolution of KOH .The bluesolutionon tretmentwith KJ inweakly acidic mediumturns yellowand producesa whiteprecipitate B identify the transitionmetalion write thechemicalreactioninvolved in theformation of A and B
Answer» Solution :An aqueousblue -colouredsolutionof atrastionmetal sulphatereacts with `H_(2)S` in acids medium to GIVE a black precipitate A which is insolublein warmaqueoussolution of `KOH` it most be ablackprecipitate of CuS becausecoppersalphate is bluecolouredalso .Theblue SOLUTIONON troatmentwith KI inweaklyacidmediumfurmyellowand producess a WHITEPRECIPITATE B inthisreaction copric iodide is formedfirst whichdecomposess to givewhitecuposeiodide iodide `CuSO_(4) + H_(2)S OVERSET("Acidic medium")rarr underset(Black)(CuSdarr) +H_(2)SO_(4)` `CuSO_(4) +2KI rarr CuI_(2) +K_(2)SO_(4)` `2CuI_(2) rarr Cu_(2)I_(2) darr +I_(2)`