Ontario Operator-in-Training (OIT) Practice Exam

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Study for the Ontario Operator-in-Training (OIT) Test. Use flashcards and multiple-choice questions for preparation, with hints and explanations for each. Get ready for your exam!

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What is the formula for total chlorine residual?

Combined chlorine + free chlorine
Chlorine demand + free chlorine
Total chlorine + combined chlorine
Chlorine dosage - chlorine residual

The correct answer is: Combined chlorine + free chlorine

The formula for total chlorine residual is defined as the sum of combined chlorine and free chlorine. In water treatment processes, free chlorine refers to the chlorine that is available to disinfect water, while combined chlorine is the chlorine that has reacted with ammonia and organic substances in the water. The total chlorine residual thus represents the total amount of chlorine that is present in the water, which includes both the active disinfecting form (free chlorine) and the form that is already engaged in reactions (combined chlorine). This understanding is crucial for water quality management, as it helps operators assess the chlorine levels in water systems and ensure effective disinfection while preventing issues like chlorine shortages or excesses.