Identify each of the following species as: Only a Brønsted acid. PO43− ClO2− NH4+ HCO3− H2PO4− Only a Brønsted base. PO43− ClO2− NH4+ HCO3− H2PO4− Both a Brønsted acid and a Brønsted base. PO43− ClO2− NH4+ HCO3− H2PO4−