Question

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. red
• B. blue
• C. green
• D. black

Answer 1

Answer: (C)

green

Answer 2

Cr2​O72−​+SO32−​H+​ Green Cr3+​+SO42−​