Which characteristic do all titration graphs share? the ph increases as the reaction progresses. the ph decreases as the reaction progresses. the midpoint of a flat horizontal section indicates the equivalence point. the midpoint of a steep vertical section indicates the equivalence point.

Answer is:The midpoint of a steep vertical section indicates the equivalence point.
Equivalence point is the point which there is stoichiometrically equivalent amounts of acid and base. 
Chemist can draw pH curve (graph showing the change in pH of a solution, which is being titrated) for titration and determine equivalence point.

The correct answer is c

Hno3(aq) → h+(aq) + no3−(aq). picture ii best represents the strong acid hno3. strong acids are strong electrolytes