Residual chlorine is detected by -
Residual chlorine is detected by, Oho-toluidine test is used to determine both free and residual chlorine with speed and accuracy. It is done using oho-toluidine dissolved in 10 per cent solution of hydrochloric acid. When added to water containing chlorine it turns yellow and its intensity varies with the concentration of the gas. Oho-toluidine Arsenite test is used to determine free and residual chlorine separately. (PARK TB (25th edition pg 775)
Horrock's test
Oho-toluidine test
Chromatography
Polarimeter
Environment and health