The chlorine or {TAIL ~ other soluble material} within the bag or sachet is dissolved or subjected to a leaching action in {HEAD ~ the liquid} 
The chlorine or { TAIL ~ other soluble material } within the bag or sachet is dissolved or subjected to a leaching action in { HEAD ~ the liquid }
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD