A white substance A reacts with dilute `H_(2)SO_(4)` is produce a colourless B and acidified `K_(2)Cr_(2)O_(7)` solution produces a green solution and a slighly coloured precipitate D .The substance B to burns in air to produce a gas E which reacts with B ito yied D and a colouless liquid .Anhyhdrous copper sulphate is turned blue on addition of this colourless liquid addition od aqueous `NH_(3) or NaOH` to C produce first a precipitate which dissolve in the excess of the respective reagent to produce a clear solution in each case identify A,B,C, and E. Write the equation of the reaction involved.

A white substance A reacts with dilute `H_(2)SO_(4)` is produce a colo

1.	A white substance A reacts with dilute `H_(2)SO_(4)` is produce a colourless B and acidified `K_(2)Cr_(2)O_(7)` solution produces a green solution and a slighly coloured precipitate D .The substance B to burns in air to produce a gas E which reacts with B ito yied D and a colouless liquid .Anhyhdrous copper sulphate is turned blue on addition of this colourless liquid addition od aqueous `NH_(3) or NaOH` to C produce first a precipitate which dissolve in the excess of the respective reagent to produce a clear solution in each case identify A,B,C, and E. Write the equation of the reaction involved.
Answer» `A = ZnS,B = H_(2)S ,C = ZnSO_(4),D =- S , E = SO_(2)` A white substance A reacts with dilute `H_(2)SO_(4)` to produce a colourless gas .B and a colourless solution C .The reaction between B and acidified `K_(2)Cr_(2)O_(7)` solution produces a green solution and a slightly coloured precipitate D.This precipitate must be sul,phate , so gas B must be hydrogen sulphide ,Sulpbuur in air to produce a gas sulphur dioxide which reacts with hydrogen sulphide to yield sulphur again and a colourless liquid water .Anhydrous copper sulphate is turned blue on addition of water a precipitate which dissolve a clear solution in excess solution of the respective regaoin to produce a clear solution in each case .This suggesist that C must be sulphate of either zine or aluminium so, A may be zine sulphide . `ZnS +H_(2)SO_(4) rarr H_(2)S + ZnSO_(4)` `Cr_(2)O_(7)^(2-) + 4H^(o+) ("From" H_(2)SO_(4)) + 3H_(2)S rarr underset("Green solution")(2Cr^(3+)) +7H_(2)O +3S darr` `S + SO_(2) rarr SO_(2)` `SO_(2) +2H_(2)S rarr 2H_(2)O +3S` `ZnSO_(4) +2NaOH rarr underset("White")(Zn(OH)_(2)darr) +Na_(2)SO_(4)` `Zn(OH)_(2) +2NaOH rarr Na_(2)ZnO_(2) +2H_(2)O`

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