Chapter 11, Problem 11.34P

Interpretation Introduction

Interpretation:

A gran plot has to be prepared for the titration data of $100.00mL$ of a weak acid by $NaOH$ and the end point has to be calculated.

Concept introduction:

Acid-base titration is titration between acid and base. It is also known as neutralization reaction.

There are primarily four types of acid-base titrations –

• Strong base vs strong acid
• Strong base vs weak acid
• Weak base vs strong acid
• Weak base vs weak acid

Equivalence point ensures the titration reaction becomes completed and at this point the number of moles of titrant and the number of moles of analyte remain equal.  The end point refers to the color change and indicates equivalence point has been reached.

Gran plot is used to determine the end point of the titration reaction.  The end point or equivalence point of the titration is determined by extrapolating the values measured previously to the equivalence point.

The Gran plot equation is,

$V_b{.10}^{-pH}=\frac{{\gamma }_{HA}}{{\gamma }_{A^{-}}}{K}_a(V_e-V_b)$

The graph of $V_b{.10}^{-pH}$ versus $V_b$ is termed as Gran plot where $V_b$ is volume of base.