This is an oxidation-reduction (redox) reaction:
6 HI + 6 e- → 6 H0 (reduction)
3 Fe0 - 6 e- → 3 FeII (oxidation)
H3PO4 is an oxidizing agent, Fe is a reducing agent.
Input interpretation
Fe + H3PO4 → Fe3(PO4)2 + H2
Iron phosphoric acid hydrogen
Balanced equation
Balance the chemical equation algebraically:
Fe + H3PO4 → Fe3(PO4)2 + H2
Add stoichiometric coefficients, c, to the reactants and products:
c1Fe + c2H3PO4 → c3 Fe3(PO4)2 + c4H2
Set the number of atoms in the reactants equal to the number of atoms in the products for Fe, H, O and P:
Fe: C1 = 3c3
H: 3c2=2c4
O: 4c2=8c3
P: c2 = 2c3
Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set c3 = 1 and solve the system of equations for the remaining coefficients:
C1 = 3 C2=2
C3 = 1 C4=3
Substitute the coefficients into the chemical reaction to obtain the balanced
equation:
Answer:
Fe + H3PO4 → Fe3(PO4)2 + H2
