$[X] + H_2SO_4 \longrightarrow [Y]$ colourless with irritating smell. $[Y] + K_2Cr_2O_7 + H_2SO_4 \longrightarrow$ Green solution. [X] and [Y] are

Question

(a) $SO_3^{2-}, SO_2$
(b) $Cl^-, HCl$
(c) $S^{2-}, H_2S$
(d) $CO_3^{2-}, CO_2$

Answer 1

Answer: $SO_3^{2-}, SO_2$

 

$[X]=SO_3^{2-}$ ion, $[Y]=SO_2$

$SO_3^{2-} + H_2SO_4 \longrightarrow SO_2 + H_2O + SO_4^{2-}$

$3SO_2 + K_2Cr_2O_7 + H_2SO_4 \longrightarrow K_2SO_4 + Cr_2(SO_4)_3$ (Green solution) $+ H_2O$