Which statement is not true for primary amines

Options

A. These forms salt with acids
B. Gives alcohols on hydrolysis
C. Gives carbyl amine reaction
D. Gives mustard oil test

Answer

To determine which statement is not true for primary amines, we will analyze each of the provided options step by step.

### Step-by-Step Solution:

1. **Understanding Primary Amines:**
- Primary amines have the general formula RNH₂, where R is an alkyl or aryl group. They contain one amino group (-NH₂) attached to a carbon atom.

2. **Evaluating the First Statement:**
- **Statement:** "Primary amines form salts with acids."
- **Explanation:** When a primary amine reacts with an acid (e.g., HCl), it forms an ammonium salt. For example, RNH₂ + HCl → RNH₃⁺Cl⁻. This statement is true.

3. **Evaluating the Second Statement:**
- **Statement:** "Primary amines give alcohols on hydrolysis."
- **Explanation:** Hydrolysis of primary amines does not yield alcohols. Instead, it leads to the formation of alkyl ammonium hydroxides. For example, RNH₂ + H₂O does not produce an alcohol. This statement is false.

4. **Evaluating the Third Statement:**
- **Statement:** "Primary amines give the carbolamine reaction."
- **Explanation:** Primary amines react with chloroform (CHCl₃) and a strong base (like KOH) to produce isocyanides (carbolamines). For example, RNH₂ + CHCl₃ + 3KOH → R-N≡C + 3KCl + 3H₂O. This statement is true.

5. **Evaluating the Fourth Statement:**
- **Statement:** "Primary amines give the mustard oil test."
- **Explanation:** Primary amines can react with carbon disulfide (CS₂) in the presence of a strong base to form thiourea derivatives, which is indicative of the mustard oil test. This statement is true.

### Conclusion:
After evaluating all statements, the statement that is **not true** for primary amines is the second one: "Primary amines give alcohols on hydrolysis."

### Final Answer:
The statement that is not true for primary amines is: **"Primary amines give alcohols on hydrolysis."**

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