Polarity is a measure of the uneven distribution of electron density within a molecule. The more polar a molecule is, the more strongly it interacts with other polar molecules (like water).

Here's why ethanol is more polar:

* Structure: Ethanol (CH3CH2OH) has a smaller carbon chain compared to propanol (CH3CH2CH2OH).

* Hydroxyl Group: Both molecules contain a hydroxyl group (-OH), which is highly polar due to the electronegativity difference between oxygen and hydrogen.

* Inductive Effect: The smaller carbon chain in ethanol allows the hydroxyl group's polarity to have a stronger influence on the molecule as a whole. The longer carbon chain in propanol somewhat "dilutes" the effect of the hydroxyl group.

In summary:

* The hydroxyl group is the main contributor to polarity.

* The smaller carbon chain in ethanol allows for a stronger influence of the hydroxyl group's polarity.

Therefore, ethanol is more polar than propanol.