Basenpuffer

Basenpuffer is a chemical buffer system that resists changes in pH in basic or alkaline ranges. In chemistry, it refers to a buffer solution based on a weak base B and its conjugate acid BH+. The mixture of B and BH+ stabilizes the pH when small amounts of acid or base are added.

How it works: In water, a weak base B partially reacts with water to form its conjugate acid BH+ and hydroxide ions (BH+ + OH−). The presence of BH+ and B creates an equilibrium that can absorb added H+ by converting B into BH+, and can absorb added OH− by converting BH+ into B. This dual action dampens shifts in pH and keeps the solution within a relatively narrow basic range.

Quantitative description is often given by the base-buffer form of the Henderson–Hasselbalch equation: pOH = pKb + log([BH+]/[B]). Since pH = 14 − pOH at 25 °C, one can determine the expected pH of the buffer from the base strength and the relative amounts of B and BH+. The effectiveness of a basenpuffer depends on the pKb of the weak base, the ratio [BH+]/[B], temperature, and ionic strength.

Common examples include ammonia and ammonium chloride in water (NH3/NH4+), which provides a basic buffer, and other systems such as carbonate/bicarbonate buffers in basic biological contexts. Basenpuffer finds use in chemical synthesis, analytical chemistry, and any setting requiring control of basic pH during reactions or measurements.