Hydrocarbons - Result Question 3

4. The major product of the following reaction is

$\mathrm{CH}_3 \mathrm{C} \equiv \mathrm{CH} \xrightarrow[\text { (ii) DI }]{\text { (i) } \mathrm{DCl} \text { (1 equiv.) }}$

(2019 Main, 9 Aprill)

(a) $\mathrm{CH}_3 \mathrm{CD}(\mathrm{Cl}) \mathrm{CHD}(\mathrm{I})$

(b) $\mathrm{CH}_3 \mathrm{CD}_2 \mathrm{CH}(\mathrm{Cl})(\mathrm{I})$

(c) $\mathrm{CH}_3 \mathrm{CD}(\mathrm{I}) \mathrm{CHD}(\mathrm{Cl})$

(d) $\mathrm{CH}_3 \mathrm{C}(\mathrm{I})(\mathrm{Cl}) \mathrm{CHD}_2$

Show Answer

Answer:

Correct Answer: 4. (d)

Solution:

  1. The major product obtained in the given reaction is $\mathrm{CH}_3 \mathrm{C}$ (I) (Cl) $\mathrm{CHD}_2$.

$\mathrm{CH}_3 \mathrm{C} \equiv \mathrm{CH} \xrightarrow[\text { 2. DI }]{\text { 1. } \mathrm{DCl} \text { (1equiv.) }} \mathrm{CH}_3 \mathrm{C}(\mathrm{I})(\mathrm{Cl}) \mathrm{CHD}_2$

Addition in unsymmetrical alkynes takes place according to Markovnikov’s rule. Reaction proceed as follows :