Determination of the concentration of carbonate using 0.1M HCl
The dissociation constant for H2CO3 are,
K1 = 4.3 x 10^-7, pK1 = 6.37
K2 = 4.67 x 10^-11, pK2 = 10.33
A solution of carbonate ion can be titrated to the hydrogen carbonate stage with HCl acid.
Equation 1 -The equivalence point for the primary stage of ionization
Equation 2 -The solution may also be titrated until all the carbonic acid is displaced.
Equation 3 -The same end point is reached by titrating hydrogen carbonate solution with HCl.
The pH of this equivalence point can be calculated if the concentrations are known. It is approximately 3.7 (for equal volumes of 0.1M HCl and 0.1M Sodium hydrogen carbonate)
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I. Calculate the concentration of carbonate solution using the data obtained for the two indicators separately.
II. Comment on the results obtained.
I. Calculate the concentration of carbonate solution.
II. Comment on the two titration readings.
III. Suggest an experiment to determine the dissociation constants of the carbonic acid. Draw the corresponding titration curve for your suggested procedure.
IV. You are provided with a solution containing a mixture of sodium hydroxide and sodium carbonate, a solution of standardized HCl and some common indicators. Describe a method to determine the concentration of sodium hydroxide and sodium carbonate in the given mixture.