At `300^(@)C, FeCl_(3)`

Options

A. decomposes into `FeCl_(2) and Cl_(2)`.
B. decomposes into `Fe and Cl_(2)`.
C. sublimes go give liquid `FeCl_(3)`
D. sublimes to give gaseous dimmer `(FeCl_(3))_(2).`

Answer

To solve the question regarding the state of FeCl₃ at 300°C, we can break down the problem into several steps:

### Step 1: Understanding the Temperature
At 300°C, we are dealing with a high temperature. This temperature is significant because it can influence the physical state of substances, including FeCl₃.

**Hint:** Consider how temperature affects the state of matter and the stability of compounds.

### Step 2: Analyzing FeCl₃
FeCl₃, or iron(III) chloride, is a compound that typically exists as a solid at room temperature. However, we need to determine how it behaves at elevated temperatures.

**Hint:** Recall the typical physical states of ionic compounds at various temperatures.

### Step 3: Stability of FeCl₃
The bond between iron (Fe) and chlorine (Cl) in FeCl₃ is relatively strong. When heated, FeCl₃ does not easily decompose into its constituent elements (Fe and Cl₂) or other compounds like FeCl₂. This is due to the stability of Fe in the +3 oxidation state compared to the +2 state.

**Hint:** Think about the oxidation states of iron and how they relate to the stability of the compound.

### Step 4: Behavior as a Lewis Acid
At high temperatures, FeCl₃ can behave as a Lewis acid. This means it can accept electron pairs from other molecules. When heated, FeCl₃ can form dimers, which are pairs of FeCl₃ molecules that bond together.

**Hint:** Consider the definition of a Lewis acid and how it interacts with other molecules.

### Step 5: Sublimation Process
When FeCl₃ is heated to 300°C, it transitions from a solid state directly to a gaseous state, a process known as sublimation. During this process, it forms gaseous dimers.

**Hint:** Recall the definition of sublimation and how it applies to solids transitioning to gases.

### Step 6: Conclusion
Based on the analysis, at 300°C, FeCl₃ sublimates to give a gaseous dimer. Therefore, the correct answer to the question is that FeCl₃ sublimates to give the gaseous dimer.

**Final Answer:** FeCl₃ sublimates to give the gaseous dimer.

---