What is indicated by a steep slope on a titration curve?

A steep slope on a titration curve indicates a rapidly changing pH. This phenomenon occurs because the titration is occurring in the vicinity of the equivalence point, where very small additions of titrant can result in significant changes in pH. The steepness reflects the presence of a highly reactive species in the solution, meaning that it is very sensitive to changes in concentration. During this phase, the solution quickly transitions between acidic and neutral or basic pH levels, indicating that the reaction between the acid and the base is approaching completion.

Other options do not accurately represent what a steep slope on a titration curve signifies. A low concentration of acid or base would not inherently cause a steep slope; instead, it might lead to a more gradual change in pH. An equal amount of reactants typically indicates that the titration has reached the equivalence point, where the pH change may slow down. A stable equilibrium point suggests that the system has settled, which would not correspond with the dramatic changes in pH associated with a steep slope in the titration curve.