NEET Organic Chemistry Some Basic Principles and Techniques — Set 12

Question 1

Which carbocation formed from $ \ce{CH3CH2CH2CH(Cl)CH3} $ via heterolytic cleavage is most stabilized by the inductive effect?

Accepted Answer

Cleavage at $ \ce{C-Cl} $ forms $ \ce{CH3CH2CH2CH+CH3} $ (secondary). A hydride shift to $ \ce{CH3CH2CH+CH2CH3} $ (secondary) is equally stable, but +I effect from alkyl groups favors it slightly more.

Question 2

Which intermediate is most stabilized by the inductive effect of alkyl groups in $ \ce{CH3CH2CH(CH3)CH2Cl} $ upon heterolytic cleavage?

Accepted Answer

Heterolytic cleavage of $ \ce{CH3CH2CH(CH3)CH2Cl} $ at $ \ce{CH2Cl} $ forms $ \ce{CH3CH2CH(CH3)CH2+} $ (primary), but a hydride shift forms $ \ce{CH3CH2C+(CH3)CH3} $ (tertiary), stabilized by the +I effect of three alkyl groups.

Question 3

Which method is used to purify an organic solid contaminated with a small amount of soluble impurity?

Accepted Answer

Crystallization removes soluble impurities by dissolving the solid in a solvent and allowing it to recrystallize.

NEET Chemistry: Organic Chemistry Some Basic Principles and Techniques — Practice Set 12

Q1. Which carbocation formed from \( \ce{CH3CH2CH2CH(Cl)CH3} \) via heterolytic cleavage is most stabilized by the inductive effect?

Q2. Which intermediate is most stabilized by the inductive effect of alkyl groups in \( \ce{CH3CH2CH(CH3)CH2Cl} \) upon heterolytic cleavage?

Q3. Which method is used to purify an organic solid contaminated with a small amount of soluble impurity?

Q4. In Lassaigne’s test, the presence of chlorine is confirmed by the formation of a white precipitate with which reagent?

Q5. A compound with molecular formula \( \ce{C5H10} \) shows chain isomerism with \( \ce{CH3CH2CH2CH=CH2} \) and lacks geometrical isomerism. What is its structure?

Q6. Which method is used to separate a mixture of organic liquids with boiling points differing by more than 30°C?

Q7. Which type of intermediate is formed when \( \ce{CH3CH2Cl} \) undergoes heterolytic cleavage?

Q8. What is the general formula of alkynes?

Q9. Which intermediate is least likely to form during the heterolytic cleavage of \( \ce{CH3CH2CH2Cl} \) in a polar solvent?

Q10. How many structural isomers are possible for \( \ce{C4H8} \) excluding stereoisomers?