Final answer:
The addition of a bitter chemical to ethylene glycol coolant is referred to as 'embitterment.' This process serves as a protective measure to deter accidental consumption of the toxic coolant.
Step-by-step explanation:
The process of adding a chemical to ethylene glycol coolant to make it taste bitter is known as 'embitterment'. The concept behind this is to prevent accidental ingestion of this chemical substance, as ethylene glycol coolant is very toxic. The bitter taste serves as a deterrent to accidental ingestion, especially by children or pets.
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