Final answer:
Catechol and quinol do not give a positive iodoform test unlike resorcinol, because they lack the required methyl ketone structure for the test.
Step-by-step explanation:
The iodoform test is commonly used in chemistry to determine the presence of certain types of methyl ketones or secondary alcohols that contain at least one methyl group adjacent to a carbonyl group. Resorcinol is known to give a positive iodoform test due to the presence of a methyl group adjacent to a carbonyl when it reacts to form a haloform.
However, neither catechol nor quinol are expected to show a positive iodoform test because they lack the necessary methyl ketone structure. Catechol consists of a benzene ring with two adjacent hydroxyl groups, and quinol is a benzene ring with two hydroxyl groups in the 1,4-position; neither of these structures is suitable for the iodoform reaction.