Well, a molecule of this carbohydrate would essentially have no electronegativity difference as it is a Nonpolar compound, and not that of a polar one. All electrons between the atoms would ultimately have a net dipole value of 0, indicating that the molecule is Nonpolar. Thus does not have a partial positive and or a partial negative charge.
Answer: -
The first step involves protonation of the carbonyl oxygen.
After protonation, the Alcohol oxygen now attacks the carbon of the carbonyl.
Thus a six membered ring is formed with 5 carbon atoms and 1 oxygen atom. The 1st position carbon atom has 2 OH groups.
One of these gets again protonated.
This leaves as water. With the loss of the H+, there results a carbonyl at 1 position.
Thus 5-hydroxypentanoic acid forms a lactone or 2-oxanone in presence of acid.
