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T1 Water alkalinity: an acid-base titration interactive exercise
A1 Milla González, Miguel
A2 Química Analítica
K1 Quantitative chemistry
K1 Acid-base titrations
K1 Alkalinity of water
K1 Carbonate in water
K1 Water analysis
K1 Bicarbonate in water
K1 Strong alkali determination in water
K1 Phenolphthalein
K1 Methyl orange
K1 Stroichiometric factors
K1 Hydrogenocarbonate in water
AB The aim of this interactive exercise is to get a deeper knowledge of acid-base titrations and to improve the user's abilities in stoichiometric calculations. An unknown 50 mL sample is titrated using sequentially the indicators phenolphthalein and methyl orange. The sample solution may contain the basic species carbonate, hydrogenocarbonate (bicarbonate) and free hydroxyl ions (from a strong alkali) individually or as a compatible binary mixture of them. The sample can be a natural water sample, but not necessarily has to be so (a lab prepared solution can mimic the natural sample). The titrant is a solution of hydrochloric acid. The required volumes of titrant are V1 (phenolphthalein endpoint) and V2 (methyl orange endpoint). From the V2/V1 ratio, the analyst must find out the qualitative composition of the sample. Then he has to calculate the amount of the species (one or more) present in the sample. To do so, it is always necessary to set up a quantitative relationship with the use of stoichiometric factors which convert the millimoles of titrant to millimoles of analyte. The calculated concentration is finally entered to be checked by the computer. All data are randomly generated and the problem composition is not given beforehand.
YR 2013
FD 2013-04-15T00:00:00Z
LK http://hdl.handle.net/10498/15136
UL http://hdl.handle.net/10498/15136
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 10-may-2026