Question

Identify the correct statements regarding organometallic compounds
• Organometallic compounds contain at least one direct metal-carbon bond
• Grignard reagents behave as strong nucleophiles and bases
• Organolithium compounds are generally more reactive than Grignard reagents
• Organometallic compounds are stable in the presence of moisture and air Choose the correct answer from the options given below:
• B, C & D Only
• A, B, C & D Only
• A, B & C Only
• B & C Only

• A. B, C & D Only
• B. A, B, C & D Only
• C. A, B & C Only
• D. B & C Only

Hint:

Key facts about organometallic compounds:
• Contain direct metal-carbon bond
• Highly reactive
• Sensitive to moisture and air
• Grignard and organolithium reagents act as strong nucleophiles

Answer 1

The Correct Option is C

Concept: Organometallic compounds are compounds containing a direct bond between a metal atom and a carbon atom of an organic group. General representation: \[ \mathrm{R-M} \] where:
• \(R\) = alkyl or aryl group
• \(M\) = metal Examples include:
• Grignard reagents: \( \mathrm{RMgX} \)
• Organolithium compounds: \( \mathrm{RLi} \) These compounds are highly reactive because carbon attached to metal acquires partial negative character.

Step 1: Examine Statement A carefully. Statement A says: “Organometallic compounds contain at least one direct metal-carbon bond.” This statement is correct. This is actually the defining characteristic of organometallic compounds. For example: \[ \mathrm{CH_3MgBr} \] contains: \[ \mathrm{C-Mg} \] bond directly. Similarly: \[ \mathrm{C-Li} \] bond exists in organolithium compounds. Therefore, Statement A is correct.

Step 2: Examine Statement B carefully. Statement B says: “Grignard reagents behave as strong nucleophiles and bases.” This statement is also correct. In Grignard reagents: \[ \mathrm{R-MgX} \] carbon attached to magnesium becomes electron rich. This happens because magnesium is highly electropositive. Thus: \[ \mathrm{R^\delta^- - Mg^\delta^+X} \] The carbon atom behaves like a carbanion. Hence Grignard reagents:
• Attack electrophiles strongly.
• Abstract protons from acidic substances. Therefore, they behave as:
• Strong nucleophiles
• Strong bases Thus, Statement B is correct.

Step 3: Examine Statement C carefully. Statement C says: “Organolithium compounds are generally more reactive than Grignard reagents.” This statement is correct. Reason:
• Lithium is more electropositive.
• \( \mathrm{C-Li} \) bond is highly polar.
• Carbon acquires greater negative character. Hence organolithium compounds are:
• More reactive
• Stronger bases
• Stronger nucleophiles than Grignard reagents. Therefore, Statement C is correct.

Step 4: Examine Statement D carefully. Statement D says: “Organometallic compounds are stable in the presence of moisture and air.” This statement is incorrect. In reality:
• Organometallic compounds react rapidly with moisture.
• Many are also sensitive to oxygen in air. For example, Grignard reagents react violently with water: \[ \mathrm{RMgX + H_2O \rightarrow RH + Mg(OH)X} \] Thus:
• Water destroys Grignard reagents.
• They must be handled in dry ether under anhydrous conditions. Hence Statement D is false.

Step 5: Identify the correct combination. We found:
• A is correct
• B is correct
• C is correct
• D is incorrect Therefore, the correct combination is: \[ \boxed{ A,\ B \ \&\ C\ \text{Only} } \]

Step 6: Match with the options. This corresponds to: \[ \boxed{(3)} \] Additional Understanding: Organometallic compounds are extremely important in:
• Carbon-carbon bond formation
• Organic synthesis
• Pharmaceutical chemistry
• Industrial catalysis Their high reactivity makes them very useful synthetic reagents. Final Conclusion: Correct statements are: \[ \boxed{ A,\ B \ \&\ C\ \text{Only} } \] Hence, the correct answer is: \[ \boxed{(3)} \]