Chlorine exists in two isotopic forms `Cl-37` and Cl-35 but its atomic mass is 35.5. this indicates the ratio of Cl-37 and Cl-35 is approximately

Options

A. `1:2`
B. `1:1`
C. `1:3`
D. `3:1`

Explanation

To determine the ratio of the isotopes Cl-37 and Cl-35 based on the average atomic mass of chlorine (35.5), we can set up an equation using the concept of weighted averages. Here's a step-by-step solution:

### Step 1: Define the Variables
Let:
- \( x \) = the fraction of Cl-35
- \( y \) = the fraction of Cl-37

Since these are the only two isotopes, we have:
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