Which of the following substance does not give iodoform test

Options

A. `C_(6)H_(5)CN`
B. `RNH_(2)`
C. `CH_(3)OH`
D. All

Answer

To determine which of the following substances does not give the iodoform test, we need to understand what the iodoform test is and which compounds typically give a positive result.

### Step-by-Step Solution:

1. **Understand the Iodoform Test**: The iodoform test is used to identify the presence of methyl ketones (R-CO-CH3) or secondary alcohols that can be oxidized to methyl ketones. A positive result is indicated by the formation of a yellow precipitate of iodoform (CHI3).

2. **Identify the Compounds**: The question provides several compounds. Let's analyze each one:
- **Methyl Ketone (CH3-CO-R)**: This will give a positive iodoform test because it contains the methyl ketone functional group.
- **Methyl Alcohol (CH3-CH2-OH)**: This compound can be oxidized to form a methyl ketone, hence it will also give a positive iodoform test.
- **Benzyl Cyanide (C6H5-CH2-CN)**: This compound does not have a methyl ketone group or a secondary alcohol that can be oxidized to form a methyl ketone. Therefore, it will not give a positive iodoform test.
- **Primary Amine (RNH2)**: Primary amines do not give the iodoform test as they do not contain the necessary functional groups.
- **Methanol (CH3-OH)**: This is a primary alcohol and does not give the iodoform test.

3. **Conclusion**: Among the given substances, Benzyl Cyanide (C6H5-CH2-CN), Primary Amine (RNH2), and Methanol (CH3-OH) do not give the iodoform test. However, since the question asks for one substance, we can conclude that Benzyl Cyanide is a clear example of a compound that does not give the iodoform test.

### Final Answer:
Benzyl Cyanide (C6H5-CH2-CN) does not give the iodoform test.