Question

select the correct answer.
which element or compound has lost electrons in this oxidation - reduction reaction?
4li + 2coo → 2co + 2li₂o
a. coo
b. li₂o
c. li
d. co
e. o

Explanation:

Step1: Analyze oxidation states

In \(CoO\), cobalt (\(Co\)) has an oxidation state of \(+ 2\) (since oxygen has an oxidation state of \(-2\) and in a neutral compound \(CoO\), \(x+(-2)=0\) where \(x\) is the oxidation state of \(Co\)). In \(Co\) (the product), the oxidation state of \(Co\) is \(0\). So \(Co\) is reduced (gains electrons).
In \(Li\), the oxidation state of \(Li\) is \(0\). In \(Li_{2}O\), lithium (\(Li\)) has an oxidation state of \(+1\) (since oxygen has an oxidation state of \(-2\) and for \(Li_{2}O\), \(2y+(-2) = 0\), solving for \(y\) gives \(y = + 1\)). So \(Li\) is oxidized (loses electrons).

Answer:

C. Li