4. Determining appropriate rate expression given two possible rate mechanisms. While drinking water disinfection has decreased waterborne diseases, it has also let to the formation of disinfection by-products (typically chlorinated compounds). Disinfection by-products have been linked, through epidemiological studies, to some diseases (e.g. bladder cancer). Monochloromethylamine, a possible disinfection by-product, can react to form a dichloromethylamine and a methylamine either by a direct mechanism or by a two- step mechanism. Water agencies have been modifying their practices to reduce disinfection by products. The first mechanism leads to a second order rate equation, the second to a first order rate expression: Direct mechanism: 2CH NHC CHNH, + CHCNC, Two step mechanism: 2CH NHCI +H2O CH_NH, +HOCI (slow) CH NHCI + HOCI CH NCI, +H,0 (fast) An experiment at pH 3.5 with [CH3NHCl] = 5.5 x 10-4 M yielded the following results: Time (min) 0 10 20 30 40 5.0 [CH3NHCl] (10-4 M) 3.12 2.28 1.79 1.47 Determine the reaction order and thus the apparent mechanism of the reaction and also determine the rate constant under the above conditions