How many electrons are removed from Cr2- when it is oxidized to CrO42-?

Assessment: WAEC SSCE - Chemistry - 1998 (Objective) Subject: Chemistry

Question 1 Report

How many electrons are removed from Cr2- when it is oxidized to CrO42-?
Answer Details
When Cr2- is oxidized to CrO42-, it gains oxygen atoms and loses electrons. To determine how many electrons are lost, we need to look at the change in oxidation state of chromium in the reaction. In Cr2-, the oxidation state of chromium is +2. In CrO42-, the oxidation state of chromium is +6. Therefore, chromium has lost 4 electrons in the reaction (going from +2 to +6). So, the correct answer is 4 electrons.
Read lesson note on Oxidation And Reduction (JAMB)
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