A mixture of three gases A,B and C is passed first into acidified `K_(2)Cr_(2)O_(7)` solution when A is absorbed turning the solution green. The remainder of the gas is passed through excess of lime water which truns milky resulting in the absorption of B. The residual gas C is absorbed by alkaline pyrogallol solution. However the original mixture does not run lead acetate paper black. Identify A,B, & C ( Give necessary equations ).