Final answer:
In the reaction between barium peroxide and nickel(II) ions, the oxidation state of nickel in the product BaNiO₃ is +2. The balanced equation for the reaction is: BaO₂ + 2Ni²+ + 2OH⁻ → BaNiO₃ + H₂O.
Step-by-step explanation:
Barium peroxide reacts with nickel(II) ions in basic solution to produce BaNiO₃. To write the balanced equation, we need to determine the oxidation state of the transition metal in the product. In this case, the transition metal is nickel (Ni). The oxidation state of nickel can be found by assigning oxidation states to the other elements in the compound and using the overall charge of the compound. Since barium has an oxidation state of +2 and oxygen has an oxidation state of -2, the oxidation state of nickel can be calculated as follows:
Barium peroxide: BaO₂ (Ba = +2, O = -2)
Nickel(II) ions: Ni²+
Product: BaNiO₃
Let the oxidation state of nickel be x.
2(+2) + x + 3(-2) = 0
4 + x - 6 = 0
x - 2 = 0
x = +2
Therefore, the oxidation state of nickel in the product BaNiO₃ is +2. The balanced equation for the reaction is:
BaO₂ + 2Ni²+ + 2OH⁻ → BaNiO₃ + H₂O