Oxidation Number And Balancing
In the compound K₂Cr₂O₇, the oxidation state of chromium is:
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About This Question
- Subject
- chemistry
- Chapter
- redox reactions and electrochemistry
- Topic
- oxidation number and balancing
- Difficulty
- Easy
- Year
- 2025
Solution
Correct Answer:
+6
In K₂Cr₂O₇, potassium has an oxidation state of +1 and oxygen has −2. Let the oxidation state of Cr be x. The sum of all oxidation states in a neutral compound is zero: 2(+1) + 2(x) + 7(−2) = 0 → 2 + 2x − 14 = 0 → 2x = 12 → x = +6. Chromium in dichromate ion always exhibits the +6 oxidation state, making it a powerful oxidising agent. This is a foundational concept for understanding redox titrations involving dichromate in acidic medium.
This easy difficulty chemistry question is from the chapter redox reactions and electrochemistry, covering the topic of oxidation number and balancing. It appeared in the 2025 exam.
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