Drop base into acid — find the exact neutralization point!
Titration is a lab technique to find the exact concentration of an unknown solution. You slowly add a known solution (the titrant) to an unknown one until they perfectly neutralize each other.
The key reaction in this experiment:
HCl + NaOH → NaCl + H₂O
An acid + a base → a salt (table salt!) + water.
The equivalence point is when exactly the right amount of base has been added to neutralize all the acid. At this point, pH = 7.0 (for strong acid + strong base).
An indicator (like phenolphthalein) changes color near the equivalence point to tell you when to stop!
Try it: Add drops slowly near 50 mL to see how dramatically the pH jumps — this is called the "pH cliff"!