Assertion: unpolluted rain | /r/HasAspect | acidic ph of about 5.2
Facets:
value: slightly
type: DEGREE
Source sentences:
text: Clean” or unpolluted rain has a slightly acidic pH of about 5.2, because carbon dioxide and water in the air react together to form carbonic acid, a weak acid (pH 5.6 in distilled water), but unpolluted rain also contains other chemicals.