Instant Notes: Analytical Chemistry

If the sample solution might react with chloride ions, for example silver or lead salts, then a double junction reference electr ...

E(cell) =E*(F-) -(RT/F) ln (a(F-)) -E(SCE) or, at 25oC: E(cell) =k -0.0257 ln (a(F-)) If a cell is constructed with a fluoride I ...

simultaneously measures the temperature so that a rapid reading of pH, compensated for temperature is obtained. The electrodes a ...

This graph shows that over the concentration range 10-^1 to 10-^5 M the calibra- tion is linear with a slope of 0.029 V/log (a(C ...

Section C – Analytical reactions in solution C4 pH AND ITS CONTROL Definition of pH The acidity or alkalinity of a reaction mixt ...

The practical (oroperational) definition of pH recognizes that it is deter- mined using electrochemical cells having an electrod ...

CH 3 COOH [ CH 3 COO-+H 3 O+ and an equilibrium constant is written (in terms of concentrations) Ka=c(Ac-)¥ c(H 3 O+)/c(HAc) = 1 ...

the pH of a mixture containing 50 cm^3 each of 0.1 M KH 2 PO 4 and 0.1 M Na 2 HPO 4 , which originally has a pH of 7.0. Adding 0 ...

[ H 3 O++ The dissociation constant of the indicator, KIn, is given by KIn=c(H 3 O+)¥ c(In-)/c(HIn) For example, for methyl oran ...

By using one of the standards described above, for example, 0.05 M potassium hydrogen phthalate, which has a pH at 25oC of 4.008 ...

Section C – Analytical reactions in solution C5 TITRIMETRY I: ACID–BASE TITRATIONS Titrimetry In order to obtain accurate quanti ...

allows the determination of volumes to 0.01 cm^3. This corresponds to about 0.05% for a typical titration volume of 20 cm^3. Wei ...

Example 1 A 25.00 cm^3 aliquot of a solution of a base of known concentration 0.1057 M is titrated with an acid of unknown conce ...

Indicators In general, indicators have two forms, which possess different colors. Indicators for acid-base titrations are themse ...

The use of electrodes, particularly the glass electrode for pH measurements and the wide range of other ion selective electrodes ...

Section C – Analytical reactions in solution C6 COMPLEXATION, SOLUBILITY AND REDOX EQUILIBRIA Complexation The formation of stab ...

M +nL =MLn bn =c (MLn)/(c (M). c (L) n) The overall formation constant is the product of the stepwise formation constants: bn =K ...

To compare the formation constants at similar pH conditions the equilibrium may be written: K’MY=KMYa 4 =c(MY(n-4)+)/(c(Mn+). cL ...

Redox equilibria In order to establish a scale of oxidative power, it is necessary to have a stan- dard, and since these reactio ...

ln K=0.67/(8.314¥ 298/(1¥ 96485)) =26.09 or K=2.1¥ 1011 Cerium(IV) oxidizes iron(II) almost completely. Examination of Table 3sh ...