Carnallite is a double chloride of K and Mg containing `38.86%` of water. 0.458 g of it gave 0.71 g AgCl and 0.666 g of it gave 0.27 g magnesium pyrophosphate `(Mg_2P_2O_7)`. Calculate the percentage of KCl in the carnallite.

Explanation

To calculate the percentage of KCl in carnallite, we will follow these steps:

### Step 1: Determine the weight of water in carnallite
Given that carnallite contains 38.86% water, we can assume we have 100 g of carnallite for simplicity. Therefore, the weight of water in 100 g of carnallite is:

\[ \text{Weight of water} = 38.86 \, \text{g} \]
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