Chapter 18.4, Problem 50SSC

Interpretation Introduction

Interpretation:

The difference between the equivalence point and the end point of a titration is to be explained.

Concept introduction:

The equivalence point and the end point of a titration give some indications about the titration.

The end point of a titration is the point at which indicator changes its color.

Answer to Problem 50SSC

The equivalence point is the $pH$ value at which $\left[H^{+}\right]fromacid=\left[O{H}^{-}\right]frombase$

The end point of a titration is the point at which indicator changes its color.

Explanation of Solution

At equivalence point,

$\left[H^{+}\right]=\left[O{H}^{-}\right]$

Equivalence point is shown in $pHvsvolume$ graph.

End point indicates that titration is completed. At end point indicator changes its color.

For example:

Phenolphthalein is colorless in basic medium but turns light pink in acidic medium.

Thus appearance of light pink color in titration of $HClvsNaOH$ shows end point that is whole $NaOH$ is neutralized.

Conclusion

Equivalence point and end points are two different quantities.

Equivalence point is a value where end point is a indication of neutralization.