Question
The oxidation state of chromium in the final product formed in the reaction between KI and acidified K _ 2 Cr _ 2 O _ 7 solution is:
JEE Main
Chemistry
d and f Block Elements
2026
JEE Main 2026 (23 January Shift 2)
JEE Main Chemistry Question (2026) — Solution
Options
- A. +6
- B. +3
- C. +4
- D. +2
Answer
B. +3
Step-by-step solution
In the reaction between KI and acidified K_2Cr_2O_7, Cr in the dichromate ion exists in +6 oxidation state. Iodide ions are oxidized to I_2 while chromium is reduced. The reduction product is Cr^ 3+ ions, which form chromium(III) salts like Cr_2(SO_4)_3 or coordination complexes. Therefore, the oxidation state of chromium in the final product is +3.
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