Two colourless gas A and B are enclosed in two separate jars. When passed through acidified `K_(2)Cr_(2)O_(7)` solution, turn the solution green. But gas A turns lead acetate paper black whereas if both the gases are passed into water, the solution develops a yellowish white turbidity. Identify the gases A and B and write balanced equations for the chemical reactions taking place.

Two colourless gas A and B are enclosed in two separate jars. When pas

1.	Two colourless gas A and B are enclosed in two separate jars. When passed through acidified `K_(2)Cr_(2)O_(7)` solution, turn the solution green. But gas A turns lead acetate paper black whereas if both the gases are passed into water, the solution develops a yellowish white turbidity. Identify the gases A and B and write balanced equations for the chemical reactions taking place.
Answer» As both gases are colourless and each of these turns acidified `K_(2)Cr_(2)O_(7)` solution green, the gases expected are `H_(2)S` and `SO_(2)` . Further, as gas A turns lead acetate paper black, it must be `H_(2)S` `underset("(Gas A)") (H_(2)S) + (CH_(3)COO)_(2)Pb rarr underset("(Black ppt.)")(PbS) + 2CH_(3)COOH` `H_(2)S` and `SO_(2)` together in aqueous solution react to produce S which gives a yellowish white turbidity `underset("(Gas A)")(2H_(2)S)+ underset("(Gas B )")(SO_(2)) rarr 2H_(2)O + underset("(Yellowish turbidity)")(3S)`