Tennessee Wastewater Operator Practice Exam

What is one gram equivalent of reactant per liter of solution called?

1. Molar solution

2. Normal solution

3. Concentration solution

4. Buffer solution

The correct answer is: Normal solution

One gram equivalent of reactant per liter of solution is referred to as a normal solution. In chemistry, normality is defined as a measure of concentration equivalent to molarity but is specifically tied to reactive species. This means that normality accounts for the number of reactive units (equivalents) that are involved in a reaction, which can vary based on the chemical context. For example, in acid-base reactions, one equivalent of an acid can donate one mole of protons, while one equivalent of a base can accept one mole of protons. Therefore, when you define a solution with respect to equivalents, you gain a clearer understanding of its potential reactivity. In contrast, molar solutions are defined simply in terms of moles of solute per liter of solution, without reference to the reactivity of the solute. Concentration solution is not a standard term used in chemistry, and while buffer solutions are essential for maintaining pH levels in a solution, they serve a different purpose than specifying the concentration of reactants in terms of equivalents.