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 state in nature
D. Mica contains the element silicon

Explanation

To determine which statement is not correct, let's analyze each statement one by one.

1. **Silicon is extensively used as a semiconductor.**
- This statement is correct. Silicon is widely used in the electronics industry as a semiconductor material due to its ability to conduct electricity under certain conditions.

2. **Carbon random is SiC.**
- This statement is also correct. Silicon carbide (SiC) is indeed a compound made from silicon and carbon, and it is used in various applications, including abrasives and electronics.

3. **Silicon occurs in free state in nature.**
- This statement is incorrect. Silicon does not occur in a free state in nature; instead, it is found primarily in the form of silica (SiO2) and silicates, which are compounds of silicon with oxygen and other elements.

4. **Silicon is a metalloid.**
- This statement is correct. Silicon is classified as a metalloid, which means it has properties of both metals and non-metals.

Based on the analysis, 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.**