NEET Organic Chemistry Some Basic Principles and Techniques — Set 11

Question 1

Which carbocation is the most stable among the following?

Accepted Answer

Tertiary carbocations are more stable due to hyperconjugation and inductive effects. $ \ce{(CH3)3C+} $ (tertiary) is more stable than primary or secondary ones.

Question 2

How many $ \sigma $ bonds are present in $ \ce{CH2=CH-CH3} $?

Accepted Answer

In $ \ce{CH2=CH-CH3} $ (propene), there are 8 single bonds (C-H and C-C) and 1 double bond (C=C). The double bond consists of 1 $ \sigma $ and 1 $ \pi $, so total $ \sigma $ bonds = 8 (single) + 1 (from double) = 9.

Question 3

Which species is most likely to act as a nucleophile in the conversion of $ \ce{CH3CH2Br} $ to $ \ce{CH3CH2CN} $?

Accepted Answer

$ \ce{CN^-} $ (cyanide ion) is a strong nucleophile that displaces $ \ce{Br^-} $ in a substitution reaction to form $ \ce{CH3CH2CN} $ (propanenitrile).

NEET Chemistry: Organic Chemistry Some Basic Principles and Techniques — Practice Set 11

Q1. Which carbocation is the most stable among the following?

Q2. How many \( \sigma \) bonds are present in \( \ce{CH2=CH-CH3} \)?

Q3. Which species is most likely to act as a nucleophile in the conversion of \( \ce{CH3CH2Br} \) to \( \ce{CH3CH2CN} \)?

Q4. Which method is used to separate a mixture of two liquids with different boiling points?

Q5. What is the shape of the carbon atom in \( \ce{CH3C#N} \) that is triple-bonded to nitrogen?

Q6. What is the IUPAC name of \( \ce{CH3CH2CH(OH)CH3} \)?

Q7. What is the shape of the carbon atom in \( \ce{CH3CH2C#CH} \) attached to the methyl group?

Q8. Which type of bond cleavage produces a carbanion?

Q9. Which of the following carbocations is least stable?

Q10. In the Dumas method, 0.28 g of a compound gave 60 mL of \( \ce{N2} \) at STP. If the compound contains only C, H, and N, what is the percentage of nitrogen?