( Therefore ( , ( ( this reaction ) ( ( occurs ( at ( ( lower pH ) ( -LRB- ( ( more ( acidic ( to ( weakly ( basic solutions ) ) ) ) ) -RRB- ) ) ) ) ) . ) ) ) )
(ROOT (S (ADVP (RB Therefore)) (, ,) (NP (DT this) (NN reaction)) (VP (VBZ occurs) (PP (IN at) (NP (NP (JJR lower) (NN pH)) (PRN (-LRB- -LRB-) (ADJP (RBR more) (JJ acidic) (PP (TO to) (NP (JJ weakly) (JJ basic) (NNS solutions)))) (-RRB- -RRB-))))) (. .)))
Therefore, this reaction occurs at lower pH (more acidic to weakly basic solutions).
(ROOT (S (PP (IN As) (NP (NN ph) (NNS increases))) (, ,) (NP (DT a) (NN solution)) (VP (VBZ becomes) (ADJP (RBR more) (JJ basic))) (. .)))