What inert materials are likely to be present in chalk, and what other indicator can be used in place of methyl orange
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The chemical composition of chalk is calcium carbonate, with minor amounts of silt and clay.[1] It is formed in the sea by sub-microscopic plankton, which fall to the sea floor and are then consolidated and compressed during diagenesis into chalk rock. Phenolpthalein is a classical pH indicator at mid range, https://www.youtube.com/watch?v=jEvhhxg2yKA
Note that different reactions take place with methyl orange vs phenolphthalein.
With methyl orange it is CO3^2- + 2H^+ ==> H2O + CO2
With phenolphthalein it is CO3^2- + H^+ ==> HCO3^-
With methyl orange it is CO3^2- + 2H^+ ==> H2O + CO2
With phenolphthalein it is CO3^2- + H^+ ==> HCO3^-
1 answer