# Balancing Redox Reactions

A reaction in which a reducing agent loses electrons while it is oxidized and the oxidizing agent gains electrons while it is reduced is called as redox (oxidation - reduction) reaction. An unbalanced redox reaction can be balanced using this calculator.

### Calculator of Balancing Redox Reactions

Redox Reaction is a chemical reaction in which oxidation and reduction occurs simultaneously and the substance which gains electrons is termed as oxidizing agent.
Refer the following table which gives you oxidation numbers.

#### Positive Ions

Valency 1Valency 2Valency 3
LithiumLi+MagnesiumMg2+AluminiumAl3+
SodiumNa+CalciumCa2+Iron IIIFe3+
PotassiumK+StrontiumSr2+ChromiumCr3+
SilverAg+BariumBa2+
HydroniumH3O+Copper IICu2+
AmmoniumNH4+ZincZn2+
Copper ICu+Manganese IIMn2+
Mercury IHg+Iron IIFe2+
Tin IISn2+

#### Negative Ions

Valency 1Valency 2Valency 3
FluorideF-OxideO2-PhosphatePO43-
ChlorideCl-SulphideS2-
BromideBr-CarbonateCO32-
IodideI-SulphateSO42-
HydroxideOH-SulphiteSO32-
NitrateNO3-DichromateCr2O72-
BicarbonateHCO3-ChromateCrO42-
BisulphateHSO3-OxalateC2O42-
NitriteNO2-ThiosulphateS2O32-
ChlorateClO3-TetrathionateS4O62-
PermanganateMnO4-Monohydrogen PhosphateHPO42-
HypochloriteOCl-
Dihydrogen PhosphateH2PO4-

#### Example: 1

##### Balance the given redox reaction:

H2+ + O22- -> H2O

Considering the equation above, we have 2 hydrogen (H) with the total charge +1[Refer the charges of the elements in the above table] and 2 oxygen (O) with the total charge -2 on the L.H.S and 2 hydrogen (H) with total charge +2 and only 1 oxygen (O) with the total charge -2 on the R.H.S. Hence with the unequal number of oxygen molecule charges, the chemical equation is said to be unbalanced.

How to balance an unbalanced chemical equation?

Let us learn here how to balance the above unbalanced equation using half reaction method with step by step procedure.

#### Given,

H+12 + O-22 -> H+12 O-2

To balance the unbalanced oxygen molecule charges, we add 2 in front of the product on R.H.S.
We get,

H+12 + O-22 -> (2) H+12 O-2

Now, we have 2 Oxygen's with the total charge -2 but 4 Hydrogen's with the total charge +4 on the R.H.S.
In order to balance the same, we add an another 2 in front of Hydrogen on the L.H.S

(2) H+12 + O-22 -> (2) H+12 O-2

Now, the equation is balanced with 4 Hydrogen's (H) with total charge +4 and 4 Oxygen's with total charge -4 on both sides.

#### Example: 2

Cr+3 + Cl-1 = Cr+3 + Cl-12

Considering the equation above, we have 1 chromium (Cr) with the total charge +3[Refer the charges of the elements in the above table] and 1 chloride (Cl) with the total charge -1 on the L.H.S and 1 chromium (Cr) with total charge +3 and only 2 chloride(Cl) with the total charge -1 on the R.H.S. Hence with the unequal number of oxygen molecule charges the chemical equation is said to be unbalanced.

How to balance an unbalanced chemical equation?

Let us learn here how to balance the above unbalanced equation with step by step procedure.

#### Given:

Cr+3 + Cl-1 = Cr+3 + Cl-12

To balance the unbalanced chloride molecule charges, we add 2 in front of the chloride on L.H.S.
We get,

Cr+3 + (2)Cl-1 = Cr+3 + Cl-12

Now, the equation is balanced with 2 Chloride's (Cl) with total charge -2 and 3 Chromium's with total charge +3 on both sides.
This is how the redox equations are balanced.