Compound used for water purification:

Ans: c (Chlorine) Ref:Park, 19 ed,p. 575Xenodiagnosis is related to -trench feverEpidemiological tetrad is related to-scrub typhusChlorine:Contact period--1 hourNo effect on spores/ protozoal cyst needs superchlorinationEffective against all virus except polio & hepatitis ABleaching powder:Iodine:* Chemically CaOC12Emergency disinfection of water* Available chlorine is 33%Contact time 20-30 min* Unstable compoundEffective over wide range of pH values* Free residual chlorine needed for effective chlorination is 0.5 mg/1. at the end of one hour contact period.Persist longer than chlorine