On the basis of the given unbalanced equation, that is:
HBr (aq) + 2NaOH (aq) → 2NaBr (s) + H2O (l)
On the right side of the equation, there are 2 atoms of sodium (Na), 2 atoms of bromine (Br), 2 atoms of hydrogen (H), and 1 atom of oxygen (O₂).
After balancing the equation correctly we get:
HBr (aq) + NaOH (aq) → NaBr (s) + H2O (l)
On the right side, one atom of Na, 1 atom of Br, 1 atom of H and one atom of O₂.