Question

An indicator that we can use to find the equivalence of a reaction is methyl orange which is a colorant and acts changing from red to yellow-orange color and its range of pH is 3.1 and 4.4, which shows its color in an acidic (weak) medium.Clearly identify the experimental equivalence point and the associated pH on the graph.

Answer 1

When we have a graph as a titration curve, we are basically seeing the "step by step" of what is happening in the reaction while we add more and more base (in an acidic solution), the pH will slowly increase, but there is a moment of a sudden increase, this is called the equivalence point, the moment in which we have an equilibrium in the molarity of acid and base, so in the graph the equivalence point will be the vertical line, that represents the sudden increase of pH, and the pH will be approximately 9, which is in the middle of the vertical line