ANS:A - 0.5 to 1

The normal dosage of chlorine in public water supply schemes typically ranges from 0.5 to 1 ppm (parts per million). Chlorine is commonly used as a disinfectant in water treatment to kill bacteria, viruses, and other harmful microorganisms present in the water. The concentration of chlorine added to the water is carefully regulated to ensure effective disinfection while minimizing potential health risks associated with excessive chlorine exposure. The range of 0.5 to 1 ppm is considered standard for maintaining water quality and safety in public water supply systems.