Question

For the following chemical reaction:

Ba²⁺(aq) + 2OH^-(aq) + H₂O₂(aq) + 2ClO₂(aq) --> Ba(ClO₂)₂(s) + 2H₂O(l) + O₂(g)
a) Assign oxidation numbers to each element.
​b) State the elements undergoing oxidation.
​c) State the elements undergoing reduction.
​d) State the oxidizing agent.
e) State the reducing agent.
​f) State the total number of electrons being transferred during the reaction.

Answer 1

Ba2+(aq) + 2OH-(aq) + H2O2(aq) + 2ClO2-(aq) --> Ba(ClO2)2(s) + 2H2O(l) + O2(g)

Rules, if atom is alone, then the charge is the oxidation number

For H =+1 typically always,

For O = -2 typically always; -1 in H2O2, and 0 in O2

For the products:

Ba = +2; O = -2; H = +1; H= +1; O = -1; Cl = +4; O = -2

For the reactants:

Ba = +2; Cl = +3; O = -2 ; H = +1; O = -2 ; O = 0 (in O2)

​b) State the elements undergoing oxidation.

oxidation is loss of electrons --> O goes from -1 in H2O2 to 0 in O2

​c) State the elements undergoing reduction.

reduction is gain in electrons

this is for Oxygen as well;

O goes from -2 in OH- to 0 in O2

​d) State the oxidizing agent.

Oxidizing agent --> typically gets reduced; this must be H2O2

e) State the reducing agent.

typically gets oxidized --> this must be OH-

​f) State the total number of electrons being transferred during the reaction.

total e- trnasfer is n = 2e-

2OH- + 2e- = O2(g) + H2(g)