Explain the answer in detail..  Q). When S O 2   is passed through acidified solution of potassium dichromate, then chromium sulphate is formed. The change in valency of chromium is  (a) +4 to +2  (b) +5 to +3  (c) +6 to +3  (d) +7 to +2

Dear Student,

Reaction Involved:

K₂Cr₂O₇ + SO₂ + 3H₂SO₄ $\to$ K₂SO₄ + Cr₂(SO₄)₃ + 3H₂O

The Oxidation state of Chromium in K₂Cr₂O₇ is:

2x + 7(-2) = -2

x = +6

And

The Oxidation State of Chromium in Cr₂(SO₄)₃ is:

2x + 3(-2) =0

x = +3

So, Oxidation state of Chromium changes from +6 to +3.

Therefore, option (c) is correct.

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