Final answer:
To find the molar mass of the organic acid HA, the moles of NaOH reacted were calculated and equated to the moles of HA due to the 1:1 mole ratio in the balanced equation. These moles were then used along with the mass of HA to determine its molar mass, which is approximately 74.1 g/mol.
Step-by-step explanation:
To calculate the molar mass of an organic acid HA, given that it reacts with 30.11 mL of 0.466 M NaOH, we start by finding the number of moles of NaOH that reacted. This can be done by multiplying the volume in liters by the molarity of NaOH:
(30.11 mL * 0.001 L/mL) * 0.466 mol/L = 0.01403126 mol NaOH
According to the balanced equation provided for the reaction (HA + NaOH → NaA + H₂O), the mole ratio of HA to NaOH is 1:1, which means an equal number of moles of HA reacted. Hence, the number of moles of HA is also 0.01403126 mol.
Finally, we use the mass of the HA sample and the number of moles of HA to calculate its molar mass using the formula:
Molar Mass = Mass of Substance (g) / Number of Moles (mol)
Molar Mass of HA = 1.040 g / 0.01403126 mol
= 74.1 g/mol