What do you undersetand by the term auto-protolysis of water ? What is its significance?

Explanation

### Step-by-Step Solution:

**Step 1: Definition of Auto-Protolysis of Water**
Auto-protolysis of water refers to the self-ionization of water, where two water molecules interact with each other. This process leads to the formation of hydronium ions (H₃O⁺) and hydroxide ions (OH⁻).

**Step 2: The Reaction**
The chemical equation representing the auto-protolysis of water is:
\[ 2 \text{H}_2\text{O} \rightleftharpoons \text{H}_3\text{O}^+ + \text{OH}^- \]
In this reaction, one water molecule donates a proton (H⁺) to another water molecule, resulting in the formation of a hydronium ion and a hydroxide ion.

**Step 3: Significance of Auto-Protolysis**
The significance of auto-protolysis of water lies in its amphoteric nature. Water can act both as an acid and a base:
- The hydronium ion (H₃O⁺) acts as an acid because it can donate a proton.
- The hydroxide ion (OH⁻) acts as a base because it can accept a proton.

This dual behavior is crucial for understanding acid-base chemistry in aqueous solutions.

**Step 4: Implications in Chemistry**
The auto-protolysis of water establishes the basis for the pH scale and the concept of neutrality in solutions. At 25°C, the concentrations of H₃O⁺ and OH⁻ in pure water are equal, leading to a neutral pH of 7.