Question

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3nio2 + 2mno2 + 2h2o + 2oh^-→2mno4^- + 3ni(oh)2
in the above reaction, the oxidation state of nickel changes from <to <.
how many electrons are transferred in the reaction?
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Explanation:

Step1: Determine the oxidation state of nickel in \(NiO_2\)

Let the oxidation state of \(Ni\) be \(x\). In \(NiO_2\), oxygen has an oxidation state of \(- 2\). Using the formula for the sum of oxidation states in a compound (\(x + 2\times(-2)=0\)), we get \(x-4 = 0\), so \(x = + 4\).

Step2: Determine the oxidation state of nickel in \(Ni(OH)_2\)

Let the oxidation state of \(Ni\) be \(y\). In \(OH^-\), oxygen has an oxidation state of \(-2\) and hydrogen has an oxidation state of \(+1\). The sum of oxidation states in \(Ni(OH)_2\) is \(y+2\times(-2 + 1)=0\). Simplifying, \(y+2\times(-1)=0\), so \(y-2=0\) and \(y = + 2\).

Step3: Calculate the change in oxidation state

The change in oxidation state of \(Ni\) is \(\Delta=+4-(+2)=+2\).

Step4: Use the relationship between change in oxidation state and electrons transferred

For each \(Ni\) atom, the change in oxidation state is \(+2\). In the reaction, there are \(3\) \(Ni\) atoms. The total change in oxidation state is \(3\times2 = 6\). According to the rules of redox reactions, the number of electrons transferred is equal to the total change in oxidation state.

Answer:

\(6\)