13-Redox_3_web - Redox titration Redox titration involves...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
Redox titration Redox titration involves oxidation-reduction reaction between analyte and titrant , and is usually carried out using an oxidizing agent as the titrant. A typical redox titration: Cerometry, Ce 4+  titrant
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The end point is detected using potentiometry . In potentiometry , a potential of the working ( or an indicator ) electrode is measured vs. a suitable reference. The working electrode is usually a Pt wire immersed in solution containing the analyte. In potentiometry, the cell voltage, E, is the analytical signal. Use the Nernst equation!  Fe 2+  can be the analyte:     Ce 4+ +  Fe 2+ Ce 3+ + Fe 3+
Background image of page 2
A typical potentiometric experimental set up for redox titration The potential of the working (or an indicator ) electrode is measured vs. a reference. The indicator electrode is usually a Pt wire immersed in solution containing the analyte. In potentiometry, the cell voltage, E, is the analytical signal.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Construction of a titration curve Our model reaction: Ce 4+ + Fe 2+ Ce 3+ + Fe 3+ At any moment of the titration the net reaction remains at  equilibrium (the Nernst eq.):   ] [ ] [ log . ] [ ] [ log . + + + = = + + + = 2 Fe 3 Fe n 0592 0 0 Fe E Fe E 3 Ce 4 Ce n 0592 0 0 Ce E Ce E where E Ce (or E Fe ) is E for the reference electrode in use, but expressed below vs. NHE. E 0 s are used; in practice, there should be formal potentials!
Background image of page 4
The reaction proceeds through   four distinctive phases (i) before titration begins ( V t =0); Fe 3+ from air (ii) titrant added, but before the equivalence point, (iii) at the equivalence point and (iv) after the equivalence point.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
(first) in addition to the Fe
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 20

13-Redox_3_web - Redox titration Redox titration involves...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online