Acid–Base Volumetric Analysis: Titration Curves

Covers acid–base volumetric analysis, where a standard solution neutralises an unknown acid or base to find its concentration. It introduces the titration curve of pH against titrant volume, naming its initial pH, buffer region, equivalence point and end point, and lists four acid–base curve types. A stepwise bench procedure follows, from preparing the burette and pipette through indicator use and the M1V1 = M2V2 calculation, ending with applications in industry, water analysis and laboratories.

Inside: 8 sections · 3 labelled pictures · 1 formula · 14 flashcards · 3 min

Topic 21 of 47 in the MU Pleven syllabus for Chemistry (Medicine, Year 1). The free AceMed note covers it in 8 sections, about 473 words (3 min of reading), with 14 flashcards.

Introduction

Acid–base volumetric analysis is an important method of quantitative analysis used to determine the concentration of an acid or a base by neutralization with a standard solution. The method is based on the reaction between an acid and a base to form salt and water. The progress of the titration can be represented graphically by a titration curve, which shows the change in pH during the titration.

Principle of Acid–Base Volumetric Analysis

The principle is based on the neutralization reaction between an acid and a base:

A solution of known concentration (standard solution) is added gradually to a solution of unknown concentration until the reaction is complete. At the equivalence point, the

amount of acid is chemically equivalent to the amount of base. The end point is detected using a suitable acid–base indicator.

Titration Curve

A titration curve is a graph plotted between pH (on Y-axis) and volume of titrant added (on X-axis).

Features of a Titration Curve:

1. Initial pH – pH of the solution before titration begins
2. Buffer region – region where pH changes slowly (in weak acid/base titrations)
3. Equivalence point – point where acid and base are present in equivalent amounts
4. End point – point where indicator changes color (close to equivalence point)

Types of Acid–Base Titration Curves:

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