Relatively {HEAD ~ base metals} such as lead and cadmium, specifically, may pass into {TAIL ~ solution} in aqueous and especially in increasingly acid environment, decomposing water and liberating hydrogen 
pass into
Relatively { HEAD ~ base metals } such as lead and cadmium , specifically , may pass into { TAIL ~ solution } in aqueous and especially in increasingly acid environment , decomposing water and liberating hydrogen
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH