`3.00` mol of `PCl_(5)` kept in `1L` closed reaction vessel was allowed to attain equilibrium at `3.80 K`. Calculate composition of the mixture at equilibrium `K_(c) = 1.80`

Explanation

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

### Step 1: Write down the given information
- Initial moles of \( PCl_5 = 3.00 \, \text{mol} \)
- Volume of the reaction vessel = \( 1 \, \text{L} \)
- Equilibrium constant \( K_c = 1.80 \)
- Reaction:
\[
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