The label of a bottle containing a solution So of hydrochloric acid carries the following indications :hydrochloric acid of density 1190g/l percentage by mass 37%. We introduce a volume V=4.2ml of So in a volumetric flask of volume 500ml containing about 100ml of distilled water and we complete the volume with distilled water until the linemark. Te new solution is noted S.
Determine the concentration of the solution S prepared.
In order to verify this concentration we titrate S by using a sloution B of potassium hydroxide of concentration 4×10^-2 mol/l. In 20ml of this solution we pour Vs ml of the solution S and we measure the pH after each addition.
V at equivalence 8.1 ml at pH 7.
Deduce theoretically the pH the solution obtained after the addition of 7mlof S to the 20ml of the basic solution .
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