In the preparation of iron (III) chloride by the action of dry chlorine on hot iron, heating is discontinued once the reaction starts. Give reason.

Explanation

To prepare iron (III) chloride (FeCl3) by the action of dry chlorine on hot iron, we follow these steps:

1. **Preparation of the Setup**: Begin by taking powdered iron in a combustion tube. This tube is suitable for conducting the reaction as it can withstand high temperatures.

2. **Heating the Iron**: Heat the powdered iron until it becomes red hot. This is crucial because chlorine gas will not react with iron at room temperature; it requires elevated temperatures to initiate the reaction.

3. **Passing Dry Chlorine Gas**: Once the iron is red hot, pass dry chlorine gas through the combustion tube. The introduction of chlorine gas is essential for the reaction to occur.

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