Dental Residual chlorine of water should be: A 1 mg/ltr after 1 hr B 1 mg/ltr after ½ hr C 0.5 mg/ltr after 1 hr D 0.5 mg/ltr after ½ hr 💡 Explanation Residual chlorine of water should be: ✓ Correct Answer: C. 0.5 mg/ltr after 1 hr