Question:medium
The suitable method that can be used for separation of products \(X\) and \(Y\) is: \[ {C6H6 →[CH3Cl/Anhyd. AlCl3] X →[dil. HNO3/H2SO4] X + Y} \]
The suitable method that can be used for separation of products \(X\) and \(Y\) is: \[ {C6H6 →[CH3Cl/Anhyd. AlCl3] X →[dil. HNO3/H2SO4] X + Y} \]
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Ortho and para nitrotoluene can be separated by fractional distillation because they have different boiling points.
Updated On: May 28, 2026
- Sublimation
- Differential extraction
- Continuous extraction
- Fractional distillation
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The Correct Option is D
Solution and Explanation
Step 1: Understanding the Topic:
This problem integrates organic synthesis (Friedel-Crafts alkylation and Nitration) with laboratory "Purification Techniques." In organic chemistry, reactions often produce mixtures of isomers (ortho, meta, para). Because these isomers have identical molecular weights, they must be separated based on differences in their physical properties like boiling points, melting points, or steam volatility.
Step 2: Key Formulas and Approach:
The approach involves identifying the products and their physical states:
Benzene + $CH_3Cl \xrightarrow{AlCl_3}$ Toluene.
Toluene + Nitrating mixture $\rightarrow$ Ortho-nitrotoluene + Para-nitrotoluene.
Choose separation method based on boiling point difference.
Step 3: Detailed Explanation:
Reaction Steps: Benzene undergoes Friedel-Crafts alkylation to form Toluene ($W$). Toluene is then nitrated. Since the methyl group is an $o/p$-directing group, the reaction produces two major isomers: ortho-nitrotoluene ($X$) and para-nitrotoluene ($Y$).
Physical Constants: These two compounds are structural isomers. Ortho-nitrotoluene has a boiling point of about $222^\circ C$, whereas para-nitrotoluene has a boiling point of about $238^\circ C$.
Method Selection: When the components of a liquid mixture have a significant difference in their boiling points (generally $>10-15^\circ C$), Fractional distillation is the most effective way to separate them. The fractionating column allows for multiple vaporization-condensation cycles, ensuring that the more volatile ortho isomer is collected first.
Step 4: Final Answer:
The suitable method is fractional distillation, matching option (A).
This problem integrates organic synthesis (Friedel-Crafts alkylation and Nitration) with laboratory "Purification Techniques." In organic chemistry, reactions often produce mixtures of isomers (ortho, meta, para). Because these isomers have identical molecular weights, they must be separated based on differences in their physical properties like boiling points, melting points, or steam volatility.
Step 2: Key Formulas and Approach:
The approach involves identifying the products and their physical states:
Benzene + $CH_3Cl \xrightarrow{AlCl_3}$ Toluene.
Toluene + Nitrating mixture $\rightarrow$ Ortho-nitrotoluene + Para-nitrotoluene.
Choose separation method based on boiling point difference.
Step 3: Detailed Explanation:
Reaction Steps: Benzene undergoes Friedel-Crafts alkylation to form Toluene ($W$). Toluene is then nitrated. Since the methyl group is an $o/p$-directing group, the reaction produces two major isomers: ortho-nitrotoluene ($X$) and para-nitrotoluene ($Y$).
Physical Constants: These two compounds are structural isomers. Ortho-nitrotoluene has a boiling point of about $222^\circ C$, whereas para-nitrotoluene has a boiling point of about $238^\circ C$.
Method Selection: When the components of a liquid mixture have a significant difference in their boiling points (generally $>10-15^\circ C$), Fractional distillation is the most effective way to separate them. The fractionating column allows for multiple vaporization-condensation cycles, ensuring that the more volatile ortho isomer is collected first.
Step 4: Final Answer:
The suitable method is fractional distillation, matching option (A).
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