Which of the following chemicals are used to manufacture methy1 isocyanate that caused Bhopal Tragedy ?
(i)Methylamine
(ii) Phosgene
(iii) Phosphine (iv) Dimethylamine .

Options

A. (i) and (iii)
B. (iii) and (iv)
C. (i) and (ii)
D. (ii) and (iv)

Explanation

To determine which chemicals are used to manufacture methyl isocyanate (MIC), we need to analyze the provided options based on the chemical reactions involved in its synthesis.

### Step-by-Step Solution:

1. **Identify the Chemicals**: The chemicals listed in the question are:
- (i) Methylamine
- (ii) Phosgene
- (iii) Phosphine
- (iv) Dimethylamine

2. **Understand the Reaction**: Methyl isocyanate is primarily synthesized from methylamine and phosgene. The reaction can be summarized as follows:
- Methylamine (CH3NH2) reacts with phosgene (COCl2).
- The reaction produces an intermediate compound, which is methyl carbamate (CH3NHCOCl), and releases hydrochloric acid (HCl).
- Upon further heating, methyl carbamate loses another molecule of HCl to form methyl isocyanate (CH3NCO).

3. **Evaluate Each Option**:
- **Methylamine (i)**: This is directly involved in the synthesis of methyl isocyanate.
- **Phosgene (ii)**: This is also directly involved in the synthesis of methyl isocyanate.
- **Phosphine (iii)**: This is not involved in the synthesis of methyl isocyanate.
- **Dimethylamine (iv)**: This is not the correct amine used in the synthesis of methyl isocyanate.

4. **Conclusion**: The chemicals used to manufacture methyl isocyanate that caused the Bhopal Tragedy are:
- Methylamine (i)
- Phosgene (ii)

Thus, the correct answer is **(i) Methylamine and (ii) Phosgene**.