Chapter 13: Titrimetric Methods: Precipitation Titrimetry

CHE 321: Quantitative Chemical AnalysisDr. Jerome Williams, Ph.D.

Saint Leo University

Overview

• Titration Basics• Primary Standards• Standard Solutions• Titration Curves

Titration Basics

• Titrimetry includes a large group of analytical methods based on determining quantity of known concentration required to react completel with analyte.

– Volumetric Gravimetric– Coulometric Redox– Amperometric Spectrophotometric

Titration Basics

• Know the following terms.

– Standard solution (titrant)– Back titration– Equivalence point– End point– Titration error– Indicators

Fig 13-1a, p.339

Fig 13-1b, p.339

Fig 13-1c, p.339

Fig 13-1d, p.339

Fig 13-1e, p.339

Primary Standards

• A primary standard is an ultrapure compound that serves as the reference material for a titrimetric analysis.

• Requirements for Primary Standards– High Purity Modest Cost– Stable Absence of hydrate water– Soluble Large Molar Mass

Standard Solutions

• A standard solution used in titrimetric analysis will be

– Stable– React rapidly with analyte– React completely with analyte to see end points– Undergo selective reaction with analyte that can be

described by balanced equation

Standard Solutions

• Overall accuracy of titrimetric analysis limited by accuracy of the concentration of standard solution used in analysis.

• Two ways to determine concentration – Direct methods– Standardization

Titration Curves

• Two types of titration curves routinely encountered in titrimetric methods; they are sigmoidal curve and linear segment curve.

Fig 13-2, p.351

Fig 13-2a, p.351

Suggested Problems

• HW Set 10: 13.2, 13.3, 13.5, 13.9• HW Set 11: 13.11, 13.14, 13.15, 13.21, 13.23