This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'The Nalgonda technique consist of what sequence of compounds addition? \nSelect and explain. \nA. Filter alum , lime , bleaching powder, B. Lime, filter alum, bleaching powder, C. Bleaching powder, lime, filter alum, D. Bleaching powder , lime, bleaching powder', 'role': 'user'}, {'content': 'Answer: A \nExplanation: - Nalgonda technique was developed at NEERI (Nagpur) in 1974 by Nawlakhe and reported by Bulusu in 1988.\n- Addition sequence is Sodium aluminate (Filter alum), lime, and bleaching powder to fluoride water – followed by Filtration, Sedimentation and Flocculation.\n- Also note in mixing:\na. rapid mixing -\xa030-60 seconds with a speed of 10-20 rpm\nb. slow mixing(during flocculation) - 10-15 minutes with 2-4 rpm speed.', 'role': 'assistant'}]