Question

Carbonic acid (H2CO3) is a weak diprotic acid with Ka1=4.43×10−7 and Ka2=4.73×10−11. When sodium bicarbonate (NaHCO3) is titrated with hydrochloric acid (HCl), it acts as a weak base according to the equation

NaHCO3(aq)+HCl(aq)→H2CO3(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 1.40 g of NaHCO3(sodium bicarbonate)?

Express your answer to three significant figures and include the appropriate units.

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Part B

What volume of 0.110 M HCl is required for the complete neutralization of 1.50 g of Na2CO3(sodium carbonate)?

Express your answer to three significant figures and include the appropriate units.