Question: what is the colour of bromothymol when added to an acid solution
[{'answer': 'magenta', 'provenance': [{'wikipedia_id': '462612', 'title': 'Bromothymol blue', 'start_paragraph_id': 4, 'start_character': 274, 'end_paragraph_id': 4, 'end_character': 281, 'bleu_score': 1.0, 'section': 'Section::::Structure and properties.\n'}]}, {'provenance': [{'wikipedia_id': '462612', 'title': 'Bromothymol blue', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 290, 'bleu_score': 0.957870874785216, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14143806903520550188}, 'section': 'Section::::Structure and properties.\n'}]}]