The pH of {TAIL ~ the aqueous solution} may be monitored through {HEAD ~ the use} of a pH meter 
The pH of { TAIL ~ the aqueous solution } may be monitored through { HEAD ~ the use } of a pH meter
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH