DISSOCIATION

dissociation, a separation or dispersal, the opposite of association. in chemistry the term is given to chemical reactions in which a substance decomposes into two or more substances, and particularly to cases in which associated molecules break down into simpler molecules. thus the reactions nh4cl <=> nh3 + hcl, and pcl5 <=> pcl3 + cl2 are instances of the first type; n2o4 <=> 2no2, of the second (see chemical action). electrolytic or ionic dissociation is the separation of a substance in solution into ions (see electrolysis; solution). dissolution (from lat. _dissolvere_, to break up into parts), the act of dissolving or reducing to constituent parts, especially of the bringing to an end an association such as a partnership or building society, and particularly of the termination of an assembly. a dissolution of parliament in england is thus the end of its existence, brought about by the efflux of time in accordance with the septennial act 1716, or by an exercise of the royal prerogative. this is done either in person, or by commission, if parliament is sitting; if prorogued, then by proclamation. the word is used as a synonym for end or death.