How many milliliters of 0.0501 M hydrobromic acid would be required to completely react with 0.1443 g of Na_2CO_3? A mixture that weighs 2.672 grams contains only potassium carbonate and potassium chloride. The entire sample is dissolved in 125 mL of deionized water and titrated with 0.1012 M hydrochloric acid. If 37.41 mL of the hydrochloric acid is required to reach a bromocresol green end point, what is the percentage of potassium carbonate in the mixture?
Carbonic acid (H2CO3) is a weak diprotic acid with Ka1=4.43Ã10â7 and Ka2=4.73Ã10â11. When sodium bicarbonate (NaHCO3) is titrated with hydrochloric acid (HCl), it acts as a weak base according to the equation
NaHCO3(aq)+HCl(aq)âH2CO3(aq)+NaCl(aq)
Suitable indicators are those that change color within the pH range for the equivalence point of a specific titration. The expected pH at the equivalence point can be calculated using pKa values. Suitable indicators for use in titrating carbonic acid or carbonate solutions are methyl orange and phenolphthalein.
Part A
What volume of 0.130 M HCl is required for the complete neutralization of 2.00 g of NaHCO3(sodium bicarbonate)?
What volume of 0.170 M HCl is required for the complete neutralization of 1.50 g of Na2CO3(sodium carbonate)?
A sample of NaOH (sodium hydroxide) contains a small amount of Na2CO3 (sodium carbonate). For titration to the phenolphthalein endpoint, 0.190 g of this sample requires 23.98 mL of 0.100 MHCl. An additional 0.700 mL of 0.100 M HCl is required to reach the methyl orange endpoint. What is the percentage of Na2CO3 by mass in the sample?