( ( When ( ( the ( water concentration ) ) ( falls ( -LRB- ( ( due ( to ( ( ( distillation or ) addition ) ( of ( a ( dehydrating agent ) ) ) ) ) ) -RRB- ) ) ) ) ) ( , ( ( the acid ) ( ( ( ( becomes ( an ( ( extremely strong ) ( oxidising agent ) ) ) ) and ) ( can ( ( react explosively ) ( with ( organic materials ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT the) (NN water) (NN concentration)) (VP (VP (VBZ falls)) (PRN (-LRB- -LRB-) (ADJP (JJ due) (PP (TO to) (NP (NP (NN distillation) (CC or) (NN addition)) (PP (IN of) (NP (DT a) (VBG dehydrating) (NN agent)))))) (-RRB- -RRB-))))) (, ,) (NP (DT the) (NN acid)) (VP (VP (VBZ becomes) (NP (DT an) (ADJP (RB extremely) (JJ strong)) (VBG oxidising) (NN agent))) (CC and) (VP (MD can) (VP (VB react) (ADVP (RB explosively)) (PP (IN with) (NP (JJ organic) (NNS materials)))))) (. .)))
When the water concentration falls (due to distillation or addition of a dehydrating agent), the acid becomes an extremely strong oxidising agent and can react explosively with organic materials.
(ROOT (S (NP (NP (DT The) (JJ strong) (NN affinity)) (PP (IN of) (NP (NP (VBN concentrated) (JJ sulfuric) (NN acid)) (PP (IN for) (NP (NN water)))))) (VP (VBZ makes) (S (NP (PRP it)) (NP (NP (DT a) (JJ good) (NN agent)) (PP (IN for) (NP (NN dehydrating)))))) (. .)))