31. Which of the following behaves as acid only? A. HCO3-
B. NH4+
C. HSO4-
D. CH3COO-

A. HCO3- is the answer.

Explanation:

HCO3- acts as an acid in the presence of OH- but as a base in the presence of HF.

for points guys

in chemistry, adhesion and cohesion are attractive forces that exist between molecules. they hold the molecules together from each other. they are different in that adhesive force exists between molecules of different substance while cohesive force happens between molecules of same substance.

adhesion between water and glass causes water molecules at the edge of water and glass interface to climb up the wall in a narrow glass tube. this is called capillary action. cohesion is what gives glass its shape and causes water to form a droplet.