Balance the following chemical equation
Na+I2->NaI

Balanced equation : 2Na+I₂⇒2NaI

Equalization of chemical reactions can be done using variables. Steps in equalizing the reaction equation:

•1. gives a coefficient on substances involved in the equation of reaction such as a, b, or c, etc.

•2. make an equation based on the similarity of the number of atoms where the number of atoms = coefficient × index (subscript) between reactant and product

•3. Select the coefficient of the substance with the most complex chemical formula equal to 1

Reaction

Na+I₂⇒NaI

aNa+bI₂⇒NaI

Na, left=a, right=1⇒a=1

I, left=2b, right=1⇒2b=1⇒b=0.5

Equation becomes :

Na+0.5I₂⇒NaI x 2

2Na+I₂⇒2NaI