Question

The dose  of KMnO4 required for disinfection of water is _______ ppm.

(a) 1-2

(b) 2-3

(c) 3-4

(d) 4-7

The question was posed to me by my college director while I was bunking the class.

My doubt stems from Methods of Disinfection topic in division Properties of Disinfection of Environmental Engineering

Answer 1

Right answer is (a) 1-2

To explain I would say: The normal dose of KMnO4 required for disinfection of water varies between 1 to 2ppm with a contact period of 4 to 6 hours.