o- toluidine reagent For chlorine estimation

o- toluidine Reagent (For chlorine estimation) A solution of o- toluidine in hydrochloric acid react with active chlorine present in water to form a yellow product. This test is applicable to water that have been treated with chlorine or hypochlorite such as potable water, swimming pools or condenser water where the residual (free) chlorine range between 0-2ppm