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The number of optically active products obtained from the complete ozonolysis of the given compound is: [cite: 364, 365]
Ozonolysis and Stereochemistry compound diagram for Q41 - JEE Main 2025 Evening
The image details a symmetrically structured long-chain polyene containing multiple internal alkene bonds and chiral carbon sites.

Solution & Explanation

### Related Formula textR_1text-CH=textCH-R_2 xrightarrow[textZn / H_2textO]textO_3 textR_1text-CHO + textR_2text-CHO ### Core Logic Complete oxidative cleavage of all double bonds via reductive ozonolysis breaks the molecule into smaller fragments: textCH_3text-CH=textCH-CH(textCH_3)text-CH=textCH-CH(textCH_3)text-CH=textCH-CH_3 Let's trace the fragmentation logic mapping visually:
Ozonolysis and Stereochemistry products diagram for Q41 - JEE Main 2025 Evening
The image details a symmetrically structured long-chain polyene containing multiple internal alkene bonds and chiral carbon sites.
### Step 1: Tracking Fragment Structures The chemical reaction outputs two major molecular product types: 1. textCH3text-CHO (Acetaldehyde): Optically inactive as it lacks a chiral carbon. 2. textOHC-CH(textCH_3)text-CHO (2-methylpropanedial): Let's inspect the substituted central carbon. It is bonded to: a hydrogen atom (-textH), a methyl group (-textCH_3), and two identical formyl groups (-textCHO). Because two of the groups are identical (-textCHO), this molecule does not have a chiral center and is entirely optically inactive. ### Step 2: Total Summation Since every single product formed is achiral, the number of optically active products is zero. ### Pattern Recognition Symmetry check shortcut: When a symmetrical dialkene is cleaved, it yields symmetric fragments. The central carbon is attached to identical flanking aldehyde units post-cleavage, destroying any prior asymmetry and leaving 0 optically active compounds. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Hydrocarbons Class 11 Chemistry: Organic Chemistry - Some Basic Principles and Techniques

Reference Study Guides

More Hydrocarbons Previous-Year Questions — Page 3

Q27 2025 Electrophilic Addition to Alkenes
Following are the four molecules "P", "Q", "R" and "S":
Electrophilic Addition to Alkenes diagram for Q27 - JEE Main 2025 Morning
The image shows four cyclic and acyclic alkene molecules labelled P, Q, R, and S.
Which one among the four molecules will react with H-Br(aq) at the fastest rate?
  • A. S
  • B. Q
  • C. R
  • D. P

Solution

### Related Formula textRate of Electrophilic Addition propto textStability of Intermediate Carbocation ### Core Logic Addition of H-Br(aq) follows an electrophilic addition pathway where a carbocation intermediate is formed in the rate-determining step. Among the given structures, compound Q forms a resonance-stabilized allylic/benzylic carbocation, rendering it highly stable compared to the others.
Electrophilic Addition to Alkenes solution diagram for Q27 - JEE Main 2025 Morning
The image shows four cyclic and acyclic alkene molecules labelled P, Q, R, and S.
### Pattern Recognition Look for conjugated or allylic systems that stabilize the positive charge dynamically via resonance. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Hydrocarbons
Q29 2025 Alkyne Reactions and Ozonolysis
Identify product [A], [B] and [C] in the following reaction sequence : CH_3-Cequiv CHfracPd/CH_2rightarrow[A]frac(i)O_3(ii)Zn,H_2Orightarrow[B]+[C]
  • A. [A]:CH_3-CH=CH_2,\ [B]: CH_3CHO,\ [C]: HCHO
  • B. [A]: CH_2=CH_2,\ [B]: H_3C-CO-CH_3,\ [C]: HCHO
  • C. [A]:CH_3-CH=CH_2,\ [B]: CH_3CHO,\ [C]: CH_3CH_2OH
  • D. [A]: CH_3CH_2CH_3,\ [B]: CH_3CHO,\ [C]: HCHO

Solution

### Related Formula Partial hydrogenation of alkynes using Pd/C yields alkenes: R-Cequiv CH + H_2 xrightarrowPd/C R-CH=CH_2 Ozonolysis cleaves the double bond to form carbonyls: R-CH=CH_2 xrightarrow(i)O_3, (ii)Zn/H_2O R-CHO + HCHO ### Core Logic Step 1: Controlled reduction of propyne gives propene: CH_3-Cequiv CH xrightarrowPd/C, H_2 CH_3-CH=CH_2 quad [A] Step 2: Reductive ozonolysis of propene ([A]) splits the alkene at the C=C bond, creating ethanal ([B]) and methanal ([C]): CH_3-CH=CH_2 xrightarrowO_3, text then Zn/H_2O CH_3CHO\ [B] + HCHO\ [C] ### Step 1: Final Identification Hence, [A] = CH_3-CH=CH_2 [B] = CH_3CHO [C] = HCHO ### Pattern Recognition Whenever an alkyne undergoes partial hydrogenation with regular catalysts, count the carbons to trace the matching alkene framework. Cleaving a terminal alkene like propene always results in formaldehyde (HCHO) as one of the fragment products. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Hydrocarbons

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