Which of the following statements is incorrect?

Options

A. Silica gel is used a drying agent
B. Silicon is extensively used as a semiconductor
C. `SiO_2` is an acidic oxide
D. Silicon exist in free state in nature

Answer

To solve the question "Which of the following statements is incorrect?", we need to analyze each statement provided in the options.

### Step-by-Step Solution:

1. **Analyze the First Statement**:
- **Statement**: "Silica gel is used as a dry agent."
- **Evaluation**: This statement is correct. Silica gel is widely used as a desiccant to absorb moisture.

2. **Analyze the Second Statement**:
- **Statement**: "Silicon is extensively used as a semiconductor."
- **Evaluation**: This statement is also correct. Silicon is a well-known semiconductor material used in electronic devices.

3. **Analyze the Third Statement**:
- **Statement**: "Silicon oxide is an acidic oxide."
- **Evaluation**: This statement is correct as well. Silicon oxide (SiO2) reacts with strong bases to form silicates, indicating its acidic nature.

4. **Analyze the Fourth Statement**:
- **Statement**: "Silicon exists in a free state in nature."
- **Evaluation**: This statement is incorrect. Silicon does not exist in a free state; it is found naturally in the form of compounds like silica (SiO2) or silicates.

### Conclusion:
The incorrect statement among the options is the fourth one: "Silicon exists in a free state in nature."

### Final Answer:
The incorrect statement is: "Silicon exists in a free state in nature."

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