Question

When SO₂ is passed through acidified K₂Cr₂O₇ solution ______.

Options

• The solution turns blue

• The solution is decolourised 

• SO₂ is reduced

• Green Cr₂(SO₄)₃ is formed

Answer 1

When SO₂ is passed through acidified K₂Cr₂O₇ solution Green Cr₂(SO₄)₃ is formed.

Explanation:

Acidified K₂Cr₂O7 is turned green due to formation of chromic sulphate

\[\ce{K2Cr2O7 + 3SO2 + H2SO4 -> K2SO4 + \underset{Green}{Cr2(SO4)3} + H2O}\]