What is association? What is dissociation?

(N/A) Association: It is the process in which two or more molecules of a solute combine to form a larger single molecule. This leads to a decrease in the total number of particles in the solution,resulting in a van't Hoff factor $(i < 1)$. For example,the dimerization of acetic acid in benzene.
Dissociation: It is the process in which a solute molecule splits into two or more simpler ions or smaller molecules when dissolved in a solvent. This leads to an increase in the total number of particles in the solution,resulting in a van't Hoff factor $(i > 1)$. For example,the dissociation of $NaCl$ into $Na^+$ and $Cl^-$ ions in water.