When exactly of solid is carefully added to exactly of a generic acidic buffer solution, its pH demo — Ionic Equilibrium Chemistry Question

💡 Solution & Explanation

Buffer capacity ($\beta$) is mathematically defined as the ratio of the number of moles of strong acid or strong base added per liter of buffer to the absolute change in its pH. The formula is $\beta = \frac{\Delta n / V}{\Delta pH}$. Here, $0.02 \text{ moles}$ of $NaOH$ are added to $1 \text{ L}$ ($V=1$), causing a pH change $\Delta pH = 5.80 - 5.75 = 0.05$. Therefore, $\beta = \frac{0.02}{0.05} = \frac{2}{5} = 0.4$.