Chemistry Regents Practice Test 2025 – The All-in-One Guide to Exam Success!

A buffer solution is characterized as a solution that resists changes in pH upon the addition of small amounts of acid or base. This is primarily because buffers typically contain a weak acid and its conjugate base, or a weak base and its conjugate acid. When an acid or base is added to a buffer, the components of the buffer react to neutralize the added substance, thereby stabilizing the pH of the solution. This property makes buffer solutions crucial in many biological and chemical processes where maintaining a consistent pH is essential for optimal function.

The other options refer to different properties or characteristics of solutions. While some solutions can change color with pH, this pertains to pH indicators rather than to the definition of a buffer. Conductivity is related to the presence of ions in a solution, and while buffers can conduct electricity, this is not what defines their function. Lastly, while some solutions can act as catalysts (accelerating chemical reactions), this does not relate to the behavior of buffers in resisting pH changes.