Ethanal and Bradys reagent. Bradys reagent is a yellow solution that is used as qualitative test for carbonyl groups associated with aldehydes and ketones and tests for a carbon-oxygen double bond. Ethanal, or acetaldehyde, (CH3CHO) is anorganic chemical compound, an important aldehyde. When ethanal is added to Bradys reagent, an orange precipitate (ethanal 2, 4-dinitrophenylhydrazone) is formed.