A certain radio isotope `._(Z)X^(A)` (half life `= 10 ` days) decays to give `._(Z-2)Y^(A-4)` . If `1.0 g` atom of `X` is kept in a sealed vessel, find the volume of helium accumulated at `STP` in `20` days ?

Explanation

To solve the problem, we need to determine the volume of helium gas produced from the decay of the radioisotope \( _{Z}^{A}X \) after 20 days. Here are the steps to arrive at the solution:

### Step 1: Determine the number of half-lives
Given that the half-life of the isotope \( _{Z}^{A}X \) is 10 days, we can calculate how many half-lives occur in 20 days.

\[ \text{Number of half-lives} = \frac{\text{Total time}}{\text{Half-life}} = \frac{20 \text{ days}}{10 \text{ days}} = 2 \]
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