( ( ( Carbon dioxide ) ( in ( the atmosphere ) ) ) ( ( is ( ( ( ( ( absorbed ( by rainfall ) ) , ) ( ( forming ( carbonic acid ) ) ( with ( ( a pH ) ( in ( ( a range ) ( of ( ( 5.6 to ) 6.2 ) ) ) ) ) ) ) ) , ) ( compared ( to ( ( the pH ) ( of ( 7 ( for ( pure water ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Carbon) (NN dioxide)) (PP (IN in) (NP (DT the) (NN atmosphere)))) (VP (VBZ is) (VP (VBN absorbed) (PP (IN by) (NP (NNS rainfall))) (, ,) (S (VP (VBG forming) (NP (JJ carbonic) (NN acid)) (PP (IN with) (NP (NP (DT a) (NN pH)) (PP (IN in) (NP (NP (DT a) (NN range)) (PP (IN of) (NP (QP (CD 5.6) (TO to) (CD 6.2)))))))))) (, ,) (PP (VBN compared) (PP (TO to) (NP (NP (DT the) (NN pH)) (PP (IN of) (NP (NP (CD 7)) (PP (IN for) (NP (JJ pure) (NN water)))))))))) (. .)))
Carbon dioxide in the atmosphere is absorbed by rainfall, forming carbonic acid with a pH in a range of 5.6 to 6.2, compared to the pH of 7 for pure water.
(ROOT (S (NP (CD 7)) (VP (VBZ is) (NP (NP (DT the) (NN ph)) (PP (IN of) (NP (JJ pure) (NN water))))) (. .)))