Which of the following is NOT a measure to control a runaway chemical reaction?

The identification of adding more reactants to the mixture as the measure that does not control a runaway chemical reaction is accurate. In the context of process safety management, runaway reactions can be defined as uncontrolled increases in temperature or pressure due to excessive reaction rates. Such reactions can lead to dangerous scenarios, including explosions or the release of hazardous substances.

Containment within the reactor is a fundamental safety measure that helps prevent the release of materials during a runaway reaction, thereby protecting both people and the environment. Emergency venting or dumping of reactants is a critical measure that allows for rapid dissipation of pressure and heat, thereby moderating the reaction before it escalates further. Crash cooling involves rapidly lowering the temperature within the reactor to slow down or halt the reaction, which is vital in preventing thermal runaway.

In contrast, adding more reactants to a mixture during a runaway reaction would increase the quantity of reactive materials present, exacerbating the situation. This would lead to a greater risk of further accelerating the reaction and enhancing the potential for accidents. Understanding this distinction is crucial in managing process safety and preventing hazardous events associated with chemical reactions.