Instant Notes: Analytical Chemistry

Section C – Analytical reactions in solution C7 TITRIMETRY II: COMPLEXATION, PRECIPITATION AND REDOX TITRATIONS During complexat ...

It is possible to titrate two cationic species in a solution by performing the titration at different pH values. However, if a s ...

The major application of complexation titrations is for the determination of the concentrations or amounts of metallic elements ...

precipitation titrations (e.g., barium with sulfate, zinc with ferrocyanide) are less commonly performed. Indicators for silver- ...

Therefore, as the reaction proceeds during titration, the ratio of the concentra- tions will change and the emf will alter. The ...

Section C – Analytical reactions in solution C8 GRAVIMETRY Gravimetry Gravimetry is one of the ‘classical’ techniques of analysi ...

time consuming. Newer instrumental methods may determine several compo- nents simultaneously, rapidly and are generally applicab ...

Weighing Modern balances can readily weigh samples directly, and masses from several grams down to a few micrograms can be weigh ...

Section C – Analytical reactions in solution C9 VOLTAMMETRY AND AMPEROMETRY Principles Voltammetric techniques involve the elect ...

The reaction that occurs is: Cu^2 ++H 2 O =Cu(s) +^1 ⁄ 2 O 2 +2H+ The copper is then deposited on the cathodeand oxygen is evolv ...

As the cadmium plates out, the layer around the electrode is depleted and more cadmium ions must diffusein from outside through ...

Table 1. Value of the half-wave potential Ion E^1 ⁄ 2 /V with respect to the SCE in 0.1 M KCl in 1 M NH 3 , NH 4 Cl Cd^2 + -0.60 ...

(ii) The reduced species (that is, the metal) is then oxidized out of the film by making the electrode increasingly anodic. A pe ...

Since the current depends on the diffusion of the oxygen to the electrode from the external solution, and this diffusion is prop ...

Section C – Analytical reactions in solution C10 CONDUCTIMETRY Movement of ions When an electric field is applied across a solut ...

C10 – Conductimetry 105 Similar rules apply to anions. Also, potassium ions and chloride ions have very similar mobilities. This ...

Lm=k/c =3.85/100 =0.0385W-^1 m^2 mol-^1 For strong electrolytes, it must be noted that, because of ionic interaction and the eff ...

C10 – Conductimetry 107 Conductimetric titrations may be carried out in nonaqueous media. For example, phenols, which are very w ...

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Section D – Separation techniques D1 SOLVENT AND SOLID-PHASE EXTRACTION The purpose of an extraction technique is physically to ...