Reactivity 3.1 – Proton transfer reactions

3.1.3 – Amphiprotic species

📌 What is an amphiprotic species?

• Certain species can act as both a Brønsted-Lowry acid AND a base depending on the substance they are interacting with. These are known as amphiprotic
• One such example of an amphiprotic species is water (H₂O)
• To be defined as an amphiprotic species, a substance must have both a lone pair of electrons (so it c an accept an H⁺ ion) as well as an H⁺ ion already in the substance (so it can donate it)
• To determine what species might be ampjoteric, we notice a trend in the periodic table
• Metal oxides are all basic, while non-metal oxides are all acidic. The acidic nature of an oxide therefore increases from left to right across a period.
• Using this logic, we can determine that amphoteric oxides form with many of the ‘metalloid’ elements (such as aluminium)