When balancing aqueous redox reactions, charge is balanced using ____.
Solution: Here, we are going to fill in the blank.
Redox reactions are the reactions in which oxidation(loss of electrons) and reduction(gain of electrons) occurs simultaneously. While balancing the redox reaction, several steps are followed:
Suppose we are to balance the equation showing the oxidation of Fe2+ ions to Fe3+ ions by dichromate ions (Cr2O7)2– in acidic medium, wherein, (Cr2O7)2– ions are reduced to Cr3+ ions. The following steps are involved in this task.Produce unbalanced equation for the reaction in ionic form :
Fe2+(aq) + (Cr2O7)2– (aq) → Fe3+ (aq) + Cr3+(aq)Separate the equation into half reactions:
Oxidation half : Fe2+ (aq) → Fe3+(aq)
Reduction half : (Cr2O7)2–(aq) → Cr3+(aq)Balance the atoms other than O and H in each half reaction individually. Here the oxidation half reaction is already balanced with respect to Fe atoms. For the reduction half reaction, we multiply the Cr3+ by 2 to balance Cr atoms
(Cr2O7)2–(aq) → 2Cr3+(aq)For reactions occurring in acidic medium, add H2O to balance O atoms and H+ to balance H atoms. Thus, we get :
(Cr2O7)2– (aq) + 14H+ (aq) → 2Cr3+(aq) + 7H2OAdd electrons to one side of the half reaction to balance the charges. If need be, make the number of electrons equal in the two half reactions by multiplying one or both half reactions by appropriate coefficients. The oxidation half reaction is thus...