How many moles of iodine are liberated when 1 mole of potassium dichromate reacts with potassium iodide

Options

(a) 1
(b) 2
(c) 3
(d) 4

Correct Answer:

3

Explanation:

Iodine is liberated from potassium iodide.
K₂Cr₂O₇ + 4H₂SO₄ → K₂ SO₄+ Cr₂(SO₄)₃ + 4H₂O+ 3[O]
[2KI + H₂SO₄+[O] → K₂ SO₄ + I₂ +H₂O] ⨯ 3 /
[ K₂Cr₂O₇ + 6KI + 7H₂ SO₄ → 4K₂ SO₄+ Cr₂(SO₄)₃ + 7H₂O + 3I₂].