Given below are two statements: Statement I: Ozonolysis followed by treatment with mathrmZn, mathrmH_2mathrmO of cis-2-butene gives ethanal. Statement II: The product obtained by ozonolysis followed by treatment with mathrmZn, mathrmH_2mathrmO of 3,6-dimethyloct-4-ene has no chiral carbon atom. In the light of the above statements, choose the correct answer from the options given below:

Solution & Explanation

### Related Formula textR_1-textCH=textCH-textR_2 xrightarrow[text(ii) Zn, H_2textO]text(i) O_3 textR_1-textCHO + textR_2-textCHO ### Core Logic Statement I: Cis-2-butene (CH_3-CH=CH-CH_3) undergoes reductive ozonolysis to cleave the double bond and yield two molecules of acetaldehyde (ethanal, CH_3CHO). This statement is true. Statement II: 3,6-dimethyloct-4-ene (CH_3-CH_2-CH(CH_3)-CH=CH-CH(CH_3)-CH_2-CH_3) undergoes reductive ozonolysis to yield 2-methylbutanal (CH_3-CH_2-CH(CH_3)-CHO). This product contains a chiral carbon atom (the C2 carbon bonded to -H, -CH_3, -CHO, and -C_2H_5). Thus, the statement that it has no chiral carbon atom is false. ### Pattern Recognition To check chirality after ozonolysis, draw the cleaved fragment structure first. Any carbon with four different groups is chiral. 2-methylbutanal has four unique groups attached to C2, making Statement II clearly false. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Hydrocarbons Class 12 Chemistry: Organic Chemistry - Some Basic Principles and Techniques

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Q84 jee_main_2024_31_jan_evening Halogenation of Alkanes (Isomers)
Number of isomeric products formed by mono-chlorination of 2-methylbutane in presence of sunlight is ________
Numerical Answer. Answer: 6 to 6

Solution

### Core Logic The structure of 2-methylbutane is CH_3-CH(CH_3)-CH_2-CH_3. It has four different types of hydrogen atoms, which can be substituted to form structural isomers: 1) 1-chloro-2-methylbutane: Chlorination at terminal CH_3 near branch. Yields a chiral center at C2 (2 enantiomers). 2) 2-chloro-2-methylbutane: Chlorination at the tertiary carbon (1 achiral product). 3) 2-chloro-3-methylbutane: Chlorination at the CH_2 group. Yields a chiral center at C2 (2 enantiomers). 4) 1-chloro-3-methylbutane: Chlorination at the far terminal CH_3. No chiral center (1 achiral product).
Halogenation of Alkanes (Isomers) diagram for Q84 - JEE Main 2024 Evening
Halogenation of Alkanes (Isomers) diagram for Q84 - JEE Main 2024 Evening
### Step 1: Counting Stereoisomers Total isomeric products = 2 (from 1st) + 1 (from 2nd) + 2 (from 3rd) + 1 (from 4th) = 6. ### Pattern Recognition When asked for "isomeric products" in halogenation without specifying "structural isomers", you must count stereoisomers (enantiomers) as well. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Hydrocarbons Class 12 Chemistry: Haloalkanes and Haloarenes
Q87 jee_main_2024_31_jan_morning Kolbe's Electrolysis
Number of alkanes obtained on electrolysis of a mixture of CH_3COONa and C_2H_5COONa is
Numerical Answer. Answer: 3 to 3

Solution

### Core Logic Kolbe's electrolytic method generates free radicals at the anode, which then combine to form alkanes. The given mixture yields two types of carboxylate radicals which decarboxylate to form alkyl radicals: CH_3COONa rightarrow dotCH_3 C_2H_5COONa rightarrow dotC_2H_5 These radicals can couple in three different ways: 1. Cross coupling: dotCH_3 + dotC_2H_5 rightarrow CH_3-CH_2-CH_3 (Propane) 2. Self-coupling 1: dotCH_3 + dotCH_3 rightarrow CH_3-CH_3 (Ethane) 3. Self-coupling 2: dotC_2H_5 + dotC_2H_5 rightarrow CH_3-CH_2-CH_2-CH_3 (Butane) Thus, a total of 3 different alkanes are formed. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 11 Chemistry: Hydrocarbons

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