A student completes a titration of an unknown diprotic acid. In this experiment, 0.79 g of the acid is dissolved in 250.0 mL of water. It requires 13.48 mL of 1.0 M NaOH to reach the second equivalence point. What is the molar mass of the acid?
This is the H2A problem and I worked that for you re the link for the post just above.
To determine the molar mass of the acid, we need to use the titration data provided.
First, let's calculate the number of moles of NaOH used in the titration:
Number of moles of NaOH = concentration of NaOH × volume of NaOH
Number of moles of NaOH = 1.0 M × 13.48 mL = 0.01348 moles
Since NaOH reacts with diprotic acid according to the equation:
2NaOH + H2A → Na2A + 2H2O,
we know that 1 mole of NaOH reacts with 1 mole of diprotic acid (H2A).
Therefore, the number of moles of the acid is also 0.01348 moles.
Now, let's calculate the molar mass of the acid:
Molar mass of the acid (H2A) = mass of the acid / number of moles of the acid
Molar mass of the acid (H2A) = 0.79 g / 0.01348 moles
Dividing the mass (0.79 g) by the moles (0.01348), we find that the molar mass of the acid is approximately 58.54 g/mol.
Therefore, the molar mass of the acid is 58.54 g/mol.