Water Disinfection
- Previous year questions on Water Disinfection for NEET PG (National Eligibility cum Entrance Test - Postgraduate), from the Community Medicine section of the exam.
- Most questions here come from previous-year papers of Indian postgraduate medical entrance and licensing exams; where a paper and year are recorded the question carries them. The image-based questions are original vignettes written around an openly licensed figure, and were never asked in any exam.
- 27 live questions in Water Disinfection.
- 4 of 27 questions carry a verified exam year: 2018, 2019, 2020.
- Community Medicine is worth about 25 of 300 questions on the exam. See every subject’s weightage.
- Question set last updated 3 Sept 2026.
Q1.What is the recommended level of chlorine in Swimming pool?
- A>0.5 mg/L
- B>0.8 mg/L
- C>1 mg/L✓ Correct answer
- D>5 mg/L
Q2.Which among the following is an active form of chlorination?
- AHypochlorite ion
- BHydrogen chloride
- CHypochlorous acid✓ Correct answer
- DChloride ion
Q3.Active disinfectant property of bleaching powder is mainly due to formation of:
- AHydrogen chloride
- BHypochloric acid
- CHypochlorous acid✓ Correct answer
- DChloramines
Q4.Recommended minimum amount of Residual chlorine in drinking water is
- A2 ppm
- B0.5 ppm✓ Correct answer
- C1.5 ppm
- D4 ppm
Q5.Value of free residual chlorine in Drinking water should be:
- A0.2 mg/L
- B0.3 mg/L
- C0.4 mg/L
- D0.5 mg/L✓ Correct answer
Q6.Disinfecting action of chlorine in chlorination of Water is mainly due to (2018)
- AChloride ion
- BHypochlorite Ion
- CHydrochloric Acid
- DHypochlorous acid✓ Correct answer
Q7.Antiseptic property of bleaching powder is due to ?
- AHypochlorous acid✓ Correct answer
- BHypochlorite
- CChlorine
- DH+
Q8.Ortho-toluidine test measures the levels of:
- ACombined chlorine
- BBoth free and combined chlorine✓ Correct answer
- CNitrates in water
- DHardness of water
Q9.Orthotoludine test can detect?
- AFree residual chlorine
- BBound chlorine
- CFree & combined chlorine✓ Correct answer
- DChlorine demand
Q10.Horrok's apparatus determines Chloride which has to have a holding level of -
- A0.1 mg/L
- B1 mg/L
- C0.01 mg
- D0.5 mg/L✓ Correct answer
Answer key
Q1: C. >1 mg/L; Q2: C. Hypochlorous acid; Q3: C. Hypochlorous acid; Q4: B. 0.5 ppm; Q5: D. 0.5 mg/L; Q6: D. Hypochlorous acid; Q7: A. Hypochlorous acid; Q8: B. Both free and combined chlorine; Q9: C. Free & combined chlorine; Q10: D. 0.5 mg/L.
Other topics in Community Medicine
- Evolution of Medicine
- Determinants and Indicators of Health
- Disease Concepts and Levels of Prevention
- Epidemiological Principles
- Descriptive Study Designs
- Analytical Study Designs: Case-Control and Cohort
- Experimental and Trial Designs
- Core Terminology in Infectious Disease Epidemiology
- Disease Transmission Dynamics
- Immunization and Vaccination Principles
- Vaccine Manufacture and Cold Chain Storage
- Disinfection and Sterilization Methods
- Screening
- Respiratory Infections of Viral Origin
- Respiratory Infections of Bacterial Origin
- Enteric and Intestinal Infections
- Arthropod-Transmitted Infections
- Viral Zoonoses
- Bacterial and Parasitic Zoonoses
- Sexually Transmitted and Surface Infections
- Cardiovascular Disease and Diabetes
- Cancer, Obesity and Blindness
- National Health Programmes: NVBDCP
- National Health Programmes: NLEP, NTEP and NACO
- National Health Programmes: NIS, JSY, RBSK and Others
- Demographic Cycle, Growth Rate and Age Pyramid
- Demographic Indicators
- Family Planning
- Preventive Care in Pregnancy, Childhood and Old Age
- Macronutrients and Energy Requirements
- Vitamins, Minerals and Water
- Food Processing, Safety and Quality
- Sociological and Psychological Concepts
- Social Structure and Health Economics
- Water Sources and Purification
- Water Quality Standards
- Climate and Environmental Meteorology
- Housing Standards and Ventilation
- Lighting, Noise and Radiation
- Refuse and Sewage Disposal
- Mosquitoes and Flies as Disease Vectors
- Ticks, Fleas and Mites as Disease Vectors
- Pest and Vector Control Measures
- Handling and Disposal of Biomedical Waste
- Disaster Preparedness and Response
- Occupational Diseases and Hazards
- ESI Scheme and the Factories Act
- Health Education and Communication Methods
- Planning and Management of Health Services
- Health Service Delivery in India
- Global Health and International Agencies
- Probability and Types of Data
- Measures of Central Tendency
- Measures of Variability and Dispersion
- Measures of Position: Percentiles and Z-Scores
- Principles of Inferential Statistics
- Hypothesis Testing Concepts
- Significance Testing Methods
- Correlation and Regression Techniques
- Clinical Research Design and Applied Biostatistics
- Community Mental Health
- Genetics in Public Health