A white solid 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 dichromate yields a green solution and a slightly coloured precipitate D. the substance D, when burnt in air, gives a gas E which reactswith B to yield D and a colourlesss liquid. anhydrous copper sulphate turns blue with this colourless liquid. the addition of aqueous NH_(3) or NaOH toC produces a precipitate that dissolves in an excess of the reagent to form a clear solution. Q. Suppose the solution obtained by the treatment off the solution C with an excess of NaOH is acidified with acetic acid and the gas B is passed through it. which of the following will obtained?

A white solid A reacts with dilute H_(2)SO_(4) to produce a colourless

1.	A white solid 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 dichromate yields a green solution and a slightly coloured precipitate D. the substance D, when burnt in air, gives a gas E which reactswith B to yield D and a colourlesss liquid. anhydrous copper sulphate turns blue with this colourless liquid. the addition of aqueous NH_(3) or NaOH toC produces a precipitate that dissolves in an excess of the reagent to form a clear solution. Q. Suppose the solution obtained by the treatment off the solution C with an excess of NaOH is acidified with acetic acid and the gas B is passed through it. which of the following will obtained?
Answer» A colourless solution A yellow PRECIPITATE A black precipitate A white precipitate Solution :One of the THREE colourless GASES `-CO_(2),SO_(2) and H_(2)S`- is generally produced by the action of dilute `H_(2)SO_(4)` on a salt. As the gas turns ACIDIFIED dichromate solution green along with the formation of slightly coloured precipitate (may be S), the gas seems to be `H_(2)S` and so the substance A seems to be a SULPHIDE. again, the action of `NH_(3)` or an NaOH solution on the solution of the substance in dilute `H_(2)SO_(4)` suggets that the substance is a zinc salt. thus, A is most likely ZnS. let us go through the reactions now.