MCQ
During the qualitative analysis of $SO _3^{2-}$ using dilute $H _2 SO _4, SO _2$ gas is evolved which turns $K _2 Cr _2 O _7$ solution (acidified with dilute $H _2 SO _4$ ):
  • A
    Black
  • B
    Red
  • Green
  • D
    Blue

Answer

Correct option: C.
Green
c
$Cr _2 O _7^{2-}+ SO _3^{2-} \stackrel{ H ^{+}}{\longrightarrow} \underset{\text { Green }}{ Cr ^{3+}}+ SO _4^{2-}$

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