What is an amphoteric substance?

An amphoteric substance is defined as one that can interact with both acids and bases, demonstrating the ability to donate protons (act as an acid) and accept protons (act as a base) depending on the chemical environment. This dual functionality allows amphoteric substances to participate in acid-base reactions in various contexts, making them versatile in chemical interactions.

For instance, water (H₂O) is a classic example of an amphoteric substance; it can donate a proton to become a hydroxide ion (OH⁻) when it acts as a base, or it can accept a proton to become a hydronium ion (H₃O⁺) when it acts as an acid.

In contrast, options that suggest a substance only acts as a base or that cannot react with water are not accurate representations of amphoteric behavior, as they limit the nature of the interactions an amphoteric substance can have. Additionally, options implying solubility only in organic solvents do not relate to the acid-base characteristics fundamental to the definition of amphotericity.