What Is the Chemical Formula for Bromine Reacting With Sodium Iodide?

Explaining chemical reactions includes the balancing of equations.
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Bromine liquid reacts with sodium iodide to produce iodine and sodium bromide. As in all equations, it is important they be balanced out. It is not accurate to write it in the form, Br + NaI → NaBr + I. Reactants and products need to be written accurately, then the equation needs to be considered as a whole. This process is called stoichiometry

1 Balancing the Equation

Bromine actually occurs in the form of a diatomic molecule. That term means two atoms, so bromine is written Br₂. The same is true of iodine. It is written I₂. Plugging these results in our initial equation results in Br₂ + NaI → NaBr + I₂. Although this equation is slightly closer to reality, it is still inaccurate.

There are two atoms of bromine and one atom of iodine on the left side of the equation and one atom of bromine and two atoms of iodine on the right side. Further balancing is required. The next adjustment, the final result, is: Br₂ + 2 NaI → I₂ + 2 NaBr. All quantities balance; the reaction is accurately explained.

Vincent Summers received his Bachelor of Science degree in chemistry from Drexel University in 1973. He furthered his education through the University of Virginia's Citizen Scholar Program program, taking many courses in organic and quantum chemistry. He has written technical articles since 2010.