'Chlorine demand' of water is defined as:
Choose the correct answer
Total chlorine gas available in cylinders
Amount of chlorine consumed by oxidising organic matter and reducing substances in water (= applied dose − residual)
Cost of chlorination per litre
Number of chlorination points
Correct Answer
B. Amount of chlorine consumed by oxidising organic matter and reducing substances in water (= applied dose − residual)
AI Detailed Explanation & IS Code Reference
Unlock the reasoning, formula path and code-linked notes inside your student dashboard.
Chlorine demand = Applied chlorine − Residual chlorine (after 30 minutes contact). Chlorine demand is consumed by: organic matter, reducing substances (Fe²⁺, Mn²⁺, H2S), ammonia (forms chloramines). The residual provides disinfection protection in distribution. Dosage = demand + desired residual. Residual target: 0.2 mg/L free chlorine at farthest point.
ScoreCardAI links this solution with subject, topic and difficulty signals so your scorecard can identify weak areas after a full mock test.
Practice more Civil Engineering questions
This MCQ belongs to JE Level Premium Test Series. Full tests include timed attempts, rank comparison and subject-wise analysis.