What happens when a strong base reacts with a strong acid?

The product of a strong acid and base reaction is water and an ionic salt; they react to neutralize acid and base properties.

For example- HCl and NaOH react together to form NaCl and H₂O.

$\mathrm{HCl}\left(aq\right)+ \mathrm{NaOH}\left(aq\right) \to \mathrm{NaCl}\left(aq\right)+\hspace{0.17em}{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

In this reaction, HCl (acid) and NaOH (base) react together to form NaCl (ionic salt) and H₂O(water) and acidic and basic properties are neutralized.