The formula of the isothiocyanate is

Options

A. `OCN^(-)`
B. `SCN^(-)`
C. `ONC^(-)`
D. `CN^(-)`

Answer

To determine the formula of isothiocyanate, we need to analyze the options provided and understand the structure of isothiocyanate.

### Step-by-Step Solution:

1. **Understanding Isothiocyanate**:
- Isothiocyanate is a compound that contains the functional group -N=C=S. It is derived from thiocyanate (SCN) by rearranging the atoms.

2. **Analyzing the Options**:
- We have four options:
- A) OCN⁻
- B) SCN⁻
- C) ONC⁻
- D) CN⁻

3. **Identifying the Correct Formula**:
- The correct formula for isothiocyanate is SCN⁻. This is because the sulfur (S) is bonded to the carbon (C) which is double bonded to nitrogen (N), forming the isothiocyanate structure.

4. **Conclusion**:
- Thus, the correct answer is option B) SCN⁻.

5. **Verifying Other Options**:
- Option A (OCN⁻) is incorrect as it represents a different compound (cyanate).
- Option C (ONC⁻) is also incorrect as it does not represent isothiocyanate.
- Option D (CN⁻) is incorrect as it does not include sulfur.

### Final Answer:
The formula of isothiocyanate is **SCN⁻**.

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