your answer will be :
B. <u>Na has a lower</u> <u>electronegativity than H</u>
because Na belongs to alkali metals which are least electronegative (most electro positive) but hydrogen is a non metal, it has higher electronegativity as compared to metals like Sodium (Na).
Yes, an OH group from ethanol can form a hydrogen bond to the ether O atom in the same way as it can do so with the single-bonded O atom in the ester.
The O atom in the carbonyl group of the ester can also form H-bonds with ethanol.
I will list them from alkaline with the lowest boiling point and alkaline with the highest.
1. C2H6
2. C9H20
3. C11H24
4. C16H34
5. C20H42
6. C32H66
7. C150H302
I have taken a quiz similar to this before and can assure you this is correct and is primarily because of the number of Carbons and Hydrogens within this. More Carbons and Hydrogens causes Boiling Points to increase because of stronger bonds.