What is meant by the end point of a reaction?

Answer 1

This is essentially equilibrium. The point at which the reaction is going forward and backward at the same rate.

Answer 2

End Point Reaction

Answer 3

The end point is a point in the titration of one substance against another in which the indicator changes color. Suppose you titrate sodium hydroxide solution against hydrochloric acid solution:

NaOH(aq) + HCl(aq) ===> NaCl(aq) + H2O

The pH of a NaCl(aq) solution is 7, neutral. But if you're using phenolphthalein indicator, the color changes only gradually at pH=8-10. That is the end point. Also, if you use methyl orange, the color changes at pH=5-6. That also is the end point.

By contrast, the equivalence point is pH=7. In practice, people don't worry about the difference between end point and equivalence point, because pH's change so fast at the end, that the error is minute.