Question

$[X] + H_2SO_4 \longrightarrow [Y]$ a colourless gas with irritating smell,$[Y] + K_2Cr_2O_7 + H_2SO_4 \longrightarrow green solution$. [X] and [Y] are:
(a) $SO_3^{2-}$, SO₂
(b) Cl⁻, HCl
(c) S²⁻, H₂S
(d) $CO_3^{2-}$, CO₂

Answer 1

1 is the answer..h2so3 reacts with h2so4 to form s02 which reacts with k2cr2o7 to give green solution which is cr2(so4)3..