( ( ( The ( ( ( acidity or ) basic ) nature ) ) ( of ( a solution ) ) ) ( is ( expressed ( as ( the pH. ) ) ) ) )
(ROOT (S (NP (NP (DT The) (ADJP (JJ acidity) (CC or) (JJ basic)) (NN nature)) (PP (IN of) (NP (DT a) (NN solution)))) (VP (VBZ is) (VP (VBN expressed) (PP (IN as) (NP (DT the) (NN pH.)))))))
The acidity or basic nature of a solution is expressed as the pH.
(ROOT (S (PP (IN As) (NP (NN ph) (NNS increases))) (, ,) (NP (DT a) (NN solution)) (VP (VBZ becomes) (ADJP (RBR more) (JJ basic))) (. .)))