Which of the following statements is not correct

Options

A. Silicon is extensively used as a semiconductor
B. Carborundum is SiC
C. Silicon occurs in free states in nature
D. Mica contains the element silicon

Explanation

To determine which statement is not correct, we need to analyze each statement provided in the video transcript.

### Step 1: Analyze the Statements

1. **Silicon is extensively used as a semiconductor.**
- This statement is **correct**. Silicon is indeed widely used in the semiconductor industry due to its excellent electrical properties.

2. **In semiconductors, we use silicon and germanium.**
- This statement is also **correct**. Both silicon (Si) and germanium (Ge) are commonly used as semiconductor materials.

3. **Carborundum is SiC (silicon carbide).**
- This statement is **correct**. Carborundum is indeed another name for silicon carbide (SiC), which is used for its hardness and thermal conductivity.

4. **Silicon occurs in free state in nature.**
- This statement is **not correct**. Silicon does not occur in a free state in nature; it is usually found in compounds, primarily as silicates and silicon dioxide (SiO2).

5. **The second most abundant element is synthetic element.**
- This statement is **not clear**. If it refers to silicon, it is not synthetic but naturally occurring. However, if it refers to aluminum, silicon, and oxygen, it could be misleading. Silicon is the second most abundant element in the Earth's crust, but aluminum is the most abundant metal.

### Conclusion
The statement that is **not correct** is: **"Silicon occurs in free state in nature."**

### Final Answer
The statement that is not correct is: **Silicon occurs in free state in nature.**

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