Final answer:
The addition of sulfuric acid (H2SO4) to carbohydrates leads to dehydration, forming furfural from pentoses and hydroxymethylfurfural from hexoses. In the presence of a base, it produces a salt and water through a neutralization reaction. With sulfur dioxide (SO2), it can produce sulfur trioxide (SO3) given heat and oxygen.
Step-by-step explanation:
After HUR, letting the product cool, and adding H2SO4 (sulfuric acid), one would expect a dehydration reaction to take place. Sulfuric acid is a strong dehydrating agent and often removes water from organic compounds. In biochemical context, adding concentrated H2SO4 to carbohydrates results in the formation of furfural from pentoses and hydroxymethylfurfural from hexoses, as H2SO4 removes the adjacent -OH groups as water (H2O) in these sugars.
When sulfuric acid reacts with a base, such as KOH (potassium hydroxide), it undergoes a neutralization reaction to form water and a salt. For instance, the reaction between H2SO4 and KOH produces potassium sulfate (K2SO4) and water (H2O). If sulfur dioxide (SO2) interacts with H2SO4, one can expect sulfur trioxide (SO3) production, given sufficient heat and oxygen, as per the following reaction: 2SO2(g) + O2(g) → 2SO3(g).