Question

For a weak acid/strong base, why is the initial region of titration curve flat? Why does the curve rise suddenly? What is special about the center point of the rapidly rising region? Why is the region after the rapid rise flat?

Answer 1

The titration curve is a graph of volume of titrant generally base vs pH. Initial region of titration curve is generally flat because solution is acting as base due to addition of strong base ;weak acid and its conjugate base formed acts as buffer so it resists any change in pH untill the added base exceeds the buffer capacity and a sharp change occurs at the equivalence point. The centre of the curve is neutralisation point but its pH is greater than 7 When a weak acid solution is neutalised the solution remains basic because of acid's conjugate base that remains in the solution. After the equivalence point omly conjugate base of weak acid is there and strong acid is being added from the beurett so no sharp rise in pH is there a flat curve is obtained.