NEET Organic Chemistry Some Basic Principles and Techniques — Set 3

Question 1

Which of the following is the general formula for alkanes?

Accepted Answer

Alkanes have only single bonds and follow the formula $ \ce{C_nH_{2n+2}} $ (e.g., $ \ce{CH4}, \ce{C2H6} $).

Question 2

A compound with molecular formula $ \ce{C3H6O} $ is a functional isomer of propanal and contains a three-carbon chain with a carbonyl group. What is its IUPAC name?

Accepted Answer

Propanal ($ \ce{CH3CH2CHO} $) is an aldehyde. Its functional isomer with a carbonyl and three-carbon chain is $ \ce{CH3COCH3} $ (propan-2-one, acetone), a ketone.

Question 3

In Lassaigne’s test, an organic compound produces a blood-red color with $ \ce{FeCl3} $ but no violet color with sodium nitroprusside. What elements are present?

Accepted Answer

Blood-red color with $ \ce{FeCl3} $ indicates nitrogen and sulphur together ($ \ce{NaSCN} $), while no violet color with sodium nitroprusside suggests sulphur alone isn’t detected, but the former confirms both.

NEET Chemistry: Organic Chemistry Some Basic Principles and Techniques — Practice Set 3

Q1. Which of the following is the general formula for alkanes?

Q2. A compound with molecular formula \( \ce{C3H6O} \) is a functional isomer of propanal and contains a three-carbon chain with a carbonyl group. What is its IUPAC name?

Q3. In Lassaigne’s test, an organic compound produces a blood-red color with \( \ce{FeCl3} \) but no violet color with sodium nitroprusside. What elements are present?

Q4. Which intermediate is most likely to form during heterolytic cleavage of \( \ce{CH3CH2CH(Cl)CH3} \) in a polar solvent?

Q5. Which carbon atom in \( \ce{CH3CH2CH2C#CH} \) has a bond angle closest to 180°?

Q6. Which species acts as a nucleophile in the formation of \( \ce{CH3CH2OH} \) from \( \ce{CH3CH2Cl} \) in a basic medium?

Q7. In Lassaigne’s test, an organic compound containing nitrogen and chlorine gives a Prussian blue color but no silver halide precipitate. What does this indicate?

Q8. Which carbon in \( \ce{CH3CH=CH2} \) has \( sp^3 \) hybridization?

Q9. Which carbon atom in \( \ce{CH3CH2C(=O)CH2CH3} \) exhibits the greatest s-character in its hybridization?

Q10. In the Carius method, halogens are converted to which type of compound for estimation?