The amount of residual chlorine left in public water supply for safety against pathogenic bacteria is about______________?

A. 1.0 to 5.0 ppm

B. 0.5 to 1.0 ppm

C. 0.01 to 0.05 ppm

D. 0.05 to 0.5 ppm

Found an error? Read our corrections policy and report it in the comments below.

Be the first to comment if anything wrong with this mcq
Your comment successfully submitted!
It will automatically posted after review and approval by our staff member.