Final answer:
The compound with the empirical formula CH₂O is acetic acid (CH₃COOH). The empirical formula represents the simplest whole-number ratio of elements in a compound, which in the case of acetic acid is CH₂O after dividing the subscripts by 2. The correct option is a.
Step-by-step explanation:
The student asked which of the compounds has the empirical formula CH₂O. The empirical formula is the value of whole-number ratio of the elements in a compound. The options given were CH₃COOH (acetic acid), C₃H₇COOH, HCOOH (formic acid), and CH₂O (formaldehyde). To find the empirical formula, we look for the simplest ratio of the elements.
For acetic acid (C₂H₄O₂), the ratio of C:H:O is 2:4:2. By dividing each subscript by the greatest common divisor, which is 2, we get 1:2:1; thus, the empirical formula is CH₂O. This matches the empirical formula we are seeking. Therefore, acetic acid (CH₃COOH) is the compound that has the empirical formula CH₂O.
For the other options, the empirical formulas would not result in CH₂O. C₃H₇COOH (option b) and HCOOH (option c) both have different ratios of carbon to hydrogen to oxygen and would not simplify to CH₂O. The actual molecular formula CH₂O (formaldehyde) is already the empirical formula.
Hence, Option a is correct.