Chemistry question?

One of the advantages of treating sewage effluent with ozone as opposed to chlorine is











a. O 3 is more effective in killing viruses





b. O 3 is more effective in killing bacteria





c. O 3 provides a residual protection against bacteria





d. O 3 is less expensive

Chemistry question?
b. Maybe. I think.





According to the first source, ozone works against bacteria, and works better than chlorine because it is a more powerful oxidizer than chlorine.





However, according to the second, there was no significant difference between chlorine and ozone in terms of effectiveness against bacteria. But this sounds like it's for a class, so it depends on what information your teacher is going from.





But by process of elimination, ozone is used to kill bacteria, so it's not a, and there seems to be no outstanding cost difference, so it's not d.





b or c. Take your pick.