Question

Chlorine is most effective as a water disinfectant at a pH of _______.

• A. 6
• B. 8
• C. 10
• D. 12

Hint:

For water disinfection with chlorine, slightly acidic conditions (pH 6) are ideal for maximizing the effectiveness of chlorine as a disinfectant.

Answer 1

The Correct Option is A

Chlorine is most effective as a water disinfectant at a slightly acidic pH. The pH of 6 is the most effective for chlorine disinfection because it helps maintain the stability and availability of chlorine in its active form, hypochlorous acid (HOCl). Final Answer: \[ \boxed{\text{(A) 6}}. \]