Question #96f09

1 Answer
Aug 6, 2016

Answer:

When it can act as a Bronsted acid (donates a proton) or a Bronsted base (accepts a proton)

Explanation:

amphiprotic substances are ions or molecules that can behave as a Bronsted acid or base.
i.e. water

  1. water is acting as an acid as it donates a proton to ammonia
    #H_2O_"(l)" + NH_(3 "(aq)") rarr OH^(-)._"(aq)" + NH_4^+._("(aq)")#

  2. Water is acting as a base when it accepts a proton from hydrochloric acid.
    #H_2O + HCl rarr H_3O^+ + Cl^-#

Another example of an amphiprotic substance is dihydrogen phosphate, #H_2PO_4^-#