Question

what aspect of water is the source of cohesion?
acidity
small size
partial charge
question 2
which of these covalent bonds is polar, based on the electronegativity of the elements?
c - h
c - o

Explanation:

1. Water cohesion is due to hydrogen - bonding which is a result of the partial charges on water molecules (oxygen is partially negative and hydrogen is partially positive). Acidity and small size are not related to cohesion.
2. A polar covalent bond has an unequal sharing of electrons due to a significant electronegativity difference between the atoms. The electronegativity of oxygen is much higher than that of carbon, creating a polar C - O bond. The electronegativity difference between carbon and hydrogen is relatively small, making the C - H bond less polar.

Answer:

Question 1: partial charge
Question 2: C - O