Answer: But-2-enoic acid and Hex-4-en-3-one are conjugated.
Butanoic acid and Hexan-3-one is non conjugated.
Step-by-step explanation:
1) Conjugated means system where double bond is present at alternative position separated by single bonds. Conjugation of electrons is present.
But-2-enoic acid is conjugated compound because double bond present at the second carbon is in conjugation with (C=O) bond of carboxylic acid
hex-4-en-3-one are conjugated because double bond present at the forth carbon is in conjugation with third carbon at which oxygen is double bonded.
2) Non conjugated means system where double bonds are not present at alternative position or double bonds are completely absent.
Butanoic acid and Hexan-3-one is non conjugated because conjugation of electrons is absent both the compounds.