Which of the following amines give mustard oil smell with `HgCl_(2)+CS_(2)`?
(I) Aniline
(II) Diethyl amine
(III) P - toluidine
(III) P - toluidine
(IV) N, N - Diethyl propanamine

Options

A. (I) & (II)
B. (II) & (IV)
C. (II) & (III)
D. (I) & (III)

Answer

To determine which of the given amines produce a mustard oil smell when reacted with HgCl2 and CS2, we need to understand the reaction involved. This reaction is known as the Hofmann mustard oil reaction, which is characteristic of primary amines.

### Step-by-Step Solution:

1. **Identify the Reaction Type**: The Hofmann mustard oil reaction occurs when a primary amine reacts with mercuric chloride (HgCl2) and carbon disulfide (CS2) to form isothiocyanates, which are responsible for the pungent mustard oil smell.

2. **Classify the Amines**: We need to classify the given amines into primary, secondary, and tertiary amines:
- **Aniline (I)**: This is a primary amine (NH2 group attached to a benzene ring).
- **Diethylamine (II)**: This is a secondary amine (two ethyl groups attached to the nitrogen).
- **P-toluidine (III)**: This is also a primary amine (NH2 group attached to a toluene ring).
- **N,N-Diethylpropanamine (IV)**: This is a tertiary amine (two ethyl groups and one propyl group attached to the nitrogen).

3. **Determine Reactivity**:
- **Primary Amines**: React with HgCl2 and CS2 to produce isothiocyanates and thus will give a mustard oil smell.
- **Secondary Amines**: Do not react in the same manner and will not produce the mustard oil smell.
- **Tertiary Amines**: Also do not react in this manner and will not produce the mustard oil smell.

4. **Evaluate Each Option**:
- **Aniline (I)**: As a primary amine, it will give a mustard oil smell.
- **Diethylamine (II)**: As a secondary amine, it will not give a mustard oil smell.
- **P-toluidine (III)**: As a primary amine, it will give a mustard oil smell.
- **N,N-Diethylpropanamine (IV)**: As a tertiary amine, it will not give a mustard oil smell.

5. **Conclusion**: The amines that will give a mustard oil smell are:
- Aniline (I)
- P-toluidine (III)

Thus, the correct answer is options I and III.

### Final Answer:
**The amines that give mustard oil smell with HgCl2 + CS2 are Aniline (I) and P-toluidine (III).**