An impure sample of calcium carbonate contains `80%` pure calcium carbonate . 25 g of the impure sample reacted with excess of hydrochloric acid. Calculate the volume of carbon dioxide at NTP obtained from this sample.

Explanation

To solve the problem step by step, we will follow these calculations:

### Step 1: Determine the amount of pure calcium carbonate in the impure sample.
Given that the impure sample contains 80% pure calcium carbonate, we can calculate the amount of pure calcium carbonate in 25 g of the impure sample.

\[ \text{Amount of pure CaCO}_3 = \left( \frac{80}{100} \right) \times 25 \text{ g} = 20 \text{ g} \]
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