Final answer:
When a reaction is not proceeding, one must assess if it's spontaneous or non-spontaneous and then investigate the presence of a catalyst or any concentration fluctuations of reactants, since these factors play critical roles in reaction progression.
Step-by-step explanation:
When a reaction is not proceeding, it's important to determine whether the reaction is spontaneous or non-spontaneous. A spontaneous reaction has the natural tendency to occur without the continual input of external energy. In contrast, a non-spontaneous reaction requires added energy to proceed. Factors that can affect the reaction include the presence of a catalyst and concentration fluctuations of reactants or products.
A catalyst can significantly increase the rate of a reaction by lowering the activation energy needed for the reaction to start, without being consumed in the process. Concentration fluctuations, according to the Law of Mass Action, influence the rate at which reactions proceed; a higher concentration of reactants typically increases the reaction rate. If a reaction is expected to be spontaneous and it is not occurring, checking for catalyst presence and ensuring proper reactant concentrations are good steps to troubleshooting the issue.