What is the product formed when 5-Hydroxy methyl furfural reacts with hot strong acid?

Levulinic acid 

The correct answer is option 3. Levulinic acid.

When 5-Hydroxymethylfurfural (HMF) reacts with hot strong acid, it undergoes further dehydration and rearrangement reactions to form levulinic acid. Levulinic acid is formed by the acid-catalyzed dehydration of HMF, leading to the loss of water molecules and the rearrangement of functional groups. This reaction is commonly carried out in acidic conditions, typically with mineral acids such as sulfuric acid. Levulinic acid is a versatile compound with various applications in the chemical industry, including as a precursor for the synthesis of pharmaceuticals, agrochemicals, and biofuels.

So, the correct answer is Levulinic acid.