When iron reacts with the oxygen and water vapour present in air, this form a layer of ________iron oxide `(Fe_(2)O_(3))`.

Options

A. reddish-brown
B. red
C. black
D. brown

Answer

To solve the question, we need to understand the reaction that occurs when iron is exposed to oxygen and water vapor in the air. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the Reactants
When iron (Fe) is exposed to the atmosphere, it reacts with two main components: oxygen (O2) and water vapor (H2O).

### Step 2: Understand the Reaction
The reaction between iron, oxygen, and water vapor leads to the formation of iron oxide. The specific type of iron oxide formed in this case is ferric oxide, which has the chemical formula Fe2O3.

### Step 3: Recognize the Product
The product of this reaction is a layer of iron oxide, specifically Fe2O3. This compound is commonly known as rust.

### Step 4: Describe the Appearance
The layer of Fe2O3 that forms on the surface of iron is typically reddish-brown in color. This characteristic color is a key identifying feature of rust.

### Step 5: Conclude the Answer
Based on the above steps, the answer to the question is that when iron reacts with oxygen and water vapor, it forms a layer of **reddish-brown** iron oxide (Fe2O3).

### Final Answer
The correct answer is: **reddish-brown**.

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