Neutral solutions have pH = 7 at 298 K. A sample of pure water is found to have pH `lt ` 7. Does it mean that it is acidic ? Explain.

Explanation

To determine whether a sample of pure water with a pH less than 7 is acidic, we need to analyze the relationship between pH, temperature, and the dissociation of water.

### Step-by-Step Solution:

1. **Understanding Neutral pH**: At 298 K (25°C), pure water is neutral with a pH of 7. This means that the concentration of hydrogen ions \([H^+]\) and hydroxide ions \([OH^-]\) is equal, both being \(1 \times 10^{-7} \, \text{M}\).

2. **Effect of Temperature on pH**: The pH of pure water can change with temperature. As the temperature increases, the dissociation of water increases, leading to a higher value of the ion product of water (\(K_w\)).

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