An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen ion, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid.
A buffer is a solution that can resist pH change upon the addition of an acidic or basic components. It is able to neutralize small amounts of added acid or base, thus maintaining the pH of the solution relatively stable.
The reference to standards in a laboratory setting often refers to an actual chemical or physical material called a metrological standard. A metrological standard is the fundamental example or reference for a unit of measure.
A reagent is a compound or mixture added to a system to start or test a chemical reaction. A reagent can be used to determine the presence or absence of a specific chemical substance as certain reactions are triggered by binding.
