Mastering the Henderson-Hasselbalch Equation
Preparing a buffer solution is a fundamental task in the science category, essential for maintaining constant pH levels in biological and chemical systems. This chemistry solver utilizes the Henderson-Hasselbalch equation to determine the equilibrium pH of a mixture containing a weak acid and its conjugate base. Whether you are working on protein purification or industrial fermentation, precision in buffer preparation is non-negotiable.
A buffer works by neutralizing small amounts of added acid or base, thereby resisting changes in pH. The effectiveness of this resistance is called buffer capacity, which depends on the total concentration of the buffering species and the proximity of the solution pH to the acid's dissociation constant (pKa).
The Scientific Method
To get accurate results from this science solver, ensure you have the correct dissociation constants. You can find these values in standard databases like the NIST Chemistry WebBook. Input your pKa, the molarity of the weak acid [HA], and the molarity of the conjugate base [A-] to find the exact pH.
Core Equation
pH = pKa + log([A⁻] / [HA])
Understanding the relationship between pH and pKa is critical. When the concentration of the acid equals the concentration of the base, the log term becomes zero, and the pH is equal to the pKa. This point represents the center of the buffer's effective range.
Chemistry FAQ
What is the range of a buffer?
Typically, a buffer is effective within ±1 unit of its pKa. Outside this range, the ratio of components becomes too lopsided to neutralize added ions effectively.
Does temperature affect pKa?
Yes. Chemical equilibrium is temperature-dependent. For high-precision work, refer to reference tables at standard lab temperatures (usually 20°C or 25°C).