Chemistry
Grade-10
Easy
Question
What is oxidation number of Cr in Cr2O72-?
- - 2
- + 2
- + 6
- + 12
Hint:
The compound has -2 charge so oxidation state of oxygen is -2.
The correct answer is: + 6
For counting oxidation state we first check whether the compound is neutral or charged. If the compound is neutral we consider total oxidation state to be zero, if charged we consider that particular charge to be the total.
Here Cr2O72- , the compound has -2 charge and oxidation state of oxygen is -2.
2(x) + 7(-2) = -2 Considering the oxidation state of Cr to be 'x'
x = +6
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