Question

$[X] + H_2 SO_4 \longrightarrow [Y]$ a colourless gas with irritating smell $[Y] + K_2 Cr_2 O_7 + H_2 SO_4 \longrightarrow$ green solution $[X]$ and $[Y]$ are

• A. $SO_3^{2-}, SO_2$
• B. $CI^-, HCI$
• C. $S^{2-} , H_2 S$
• D. $CO_3^{2-} , CO_2$

Answer 1

Answer: (A)

$SO_3^{2-}, SO_2$

Answer 2

$\underset {X}{SO_3^{2-}} + H_2 SO_4 \longrightarrow \underset {Y}{SO_2 \ \uparrow} + H_2 O + SO_4^{2-}$
$SO_2$ is a colourless gas with irritating odour.
$\underset{Y}{3SO_2} + K_2 Cr_2 O_7 + H_2 SO_4 \longrightarrow K_2 SO_4 + \underset{Green \\\ solution}{Cr_2(SO_4)_3} + H_2 O$