Horrok's apparatus determines Chloride which has to have a holding level of -
Ans. is 'd' i.e., 0.5 mg/L Horrock's apparatus is used to find out the dose of bleaching powder required for disinfection of water by chlorination. o The principle in chlorination is to ensure a free residual chlorine o10.5 mg/litre at the end of one hour contact.
0.1 mg/L
1 mg/L
0.01 mg
0.5 mg/L