{"knowledge_schema": {"broad_category": "Chemistry \u2192 Organic Chemistry \u2192 Spectroscopy and Structural Identification", "refinement": "This problem involves identifying an organic compound based on spectral data, including mass spectrometry, infrared spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy.", "specific_scope": "The task is to analyze the provided spectral data to suggest a reasonable structure for the unidentified compound from a list of candidates.", "goal": "Determine the most likely structure of the unidentified compound based on the provided spectral information."}, "summary": "In this problem, we are tasked with identifying an organic compound using spectral data. The molecular ion peak at m/z = 156 suggests a molecular weight of 156 g/mol, while the presence of a peak at m/z = 158 indicates a possible isotopic pattern, likely due to chlorine. The IR spectrum shows a broad peak indicative of an -OH group and a strong peak at 1720 cm^-1, suggesting a carbonyl group (C=O). The 1H NMR data indicates the presence of aromatic protons and a singlet, which could correspond to a hydroxyl group. Given these clues, the most reasonable structural suggestion from the candidates is 3-Chloro-2-hydroxybenzaldehyde, as it fits the spectral data and molecular weight."}