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