Question: what type of reaction is the rusting of iron
[{'answer': 'electrochemical', 'provenance': [{'wikipedia_id': '26477', 'title': 'Rust', 'start_paragraph_id': 9, 'start_character': 212, 'end_paragraph_id': 9, 'end_character': 227, 'bleu_score': 1.0, 'section': 'Section::::Chemical reactions.:Oxidation of iron.\n'}]}, {'provenance': [{'wikipedia_id': '26477', 'title': 'Rust', 'start_paragraph_id': 9, 'start_character': 0, 'end_paragraph_id': 9, 'end_character': 581, 'bleu_score': 0.9792717993254391, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5635174265639191631}, 'section': 'Section::::Chemical reactions.:Oxidation of iron.\n'}]}]