Question

when is down arrow used in a chemical reaction​

Answer 1

The up arrow being directed towards the top means that the compound or any gas that has been formed is “escaped” or “liberated” during a chemical reaction where as down arrow means that the compounds which is formed being insoluble is settled down , which we call in chemistry as “precipitates” out.

Answer 2

Answer:

down arrow in a chemical equation represents and signifies a precipitate formed by reaction of an acid and a base. this reaction is called precipitation/precipitate reaction.