Question

One (1) l of a buffer solution is prepared from 0.300 mol of bicarbonate ion and 0.540 mol of sodium carbonate. The pk of the bicarbonate ion is 10.2. If the base was not present (that is, you have only the acid), what would the pH be?

Answer 1

To calculate the pH with only the bicarbonate ion present, one can use the Henderson-Hasselbalch equation. Since the conjugate acid is absent, the equation simplifies, indicating the pH would approximately equal the pKa of bicarbonate, which is 10.2.

Step-by-step explanation:

To calculate the pH of a solution containing only the bicarbonate ion without the presence of the base sodium carbonate, we can use the Henderson-Hasselbalch equation. The equation is:

However, since there is no conjugate acid present (it has been mentioned that only the bicarbonate ion, which acts as the base, is present), the pH would be determined solely by the bicarbonate ion concentration. The Henderson-Hasselbalch equation simplifies to:

Given that the pKa of bicarbonate is 10.2, the pH would be approximately equal to 10.2, assuming that the concentration of bicarbonate ions significantly exceeds the concentration of hydronium ions produced by its dissociation in water.