Which of the following can be amphoteric?
A) Cl¯ B) H3O+ C) HPO4¯ D) PO4¯³ E) HCl
Try C.
To determine which of the given substances can be amphoteric, we need to understand what amphoteric means.
Amphoteric substances are those that can act as both acids and bases. They have the ability to either gain or lose a proton (H+ ion), depending on the conditions.
In each option, we can analyze the potential for each substance to act as an acid or a base:
A) Cl¯: Chloride ion is the conjugate base of hydrochloric acid (HCl), which is a strong acid. Chloride ion cannot act as an acid or a base, so it is not amphoteric.
B) H3O+: This is the hydronium ion and is formed when water (H2O) acts as an acid by donating a proton. Hydronium ion is the conjugate acid of water, but it cannot donate a proton further. So, it cannot act as a base, and is not amphoteric.
C) HPO4¯: Hydrogen phosphate ion can act as both an acid and a base. It can donate a proton to form the phosphate ion (PO4¯³). Therefore, it is amphoteric.
D) PO4¯³: Phosphate ion is the conjugate base of hydrogen phosphate (HPO4¯). It can accept a proton to form hydrogen phosphate ion. Therefore, it can act as a base and is amphoteric.
E) HCl: Hydrochloric acid (HCl) is a strong acid and can only act as an acid. It cannot accept a proton and is not amphoteric.
Therefore, the substances that can be amphoteric are:
C) HPO4¯
D) PO4¯³