Final answer:
To determine the mass of anhydrous sodium carbonate for a pH 10.95424251 buffer, use the Henderson-Hasselbalch equation. A specific mass cannot be provided without additional details such as exact pH value and buffer concentration.
Step-by-step explanation:
To calculate the mass of anhydrous sodium carbonate required to prepare a hydrogen carbonate ion/carbonate ion buffer with an assigned pH of 10.95424251, you need to apply the Henderson-Hasselbalch equation. Given the pKa of 10.33 for the carbonic acid/bicarbonate buffering system, the equation becomes pH = pKa + log([A-]/[HA]), where [A-] is the concentration of the carbonate ion (CO32-) and [HA] is the concentration of the bicarbonate ion (HCO3-).
In this case, the pH is higher than the pKa, indicating there should be more [A-] than [HA]. Because precise calculations would require additional information such as the exact pH specification and total buffer concentration, it's not possible to provide a specific mass without that data. Generally, to prepare the buffer, you would weigh out the necessary amounts of sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3), then dilute to 250 mL.