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cis and trans alkenes from partial reduction of an alkyne (Lindlar catalyst vs Na in liquid NH3)

This type of question, asked 4 times: 31 Jan 2023, 1 Feb 2023, 1 Feb 2024, 23 Jan 2026 S1. All 4 questions below, oldest first.

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  1. Question 1

    31 Jan 2023

    35
    Choose the correct set of reagents for the following conversion. trans (Ph−CH=CH−CH3)→cis(Ph−CH=CH−CH3)\left( Ph - CH = CH -CH_{3} \right)\rightarrow cis\left( Ph - CH = CH -CH_{3} \right)

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  2. Question 2

    1 Feb 2023

    36
    But-2-yne is reacted separately with one mole of Hydrogen as shown below: A. A is more soluble than B. B. The boiling point & melting point of A are higher and lower than B respectively. C. A is more polar than B because dipole moment of A is zero. D. Br2Br_{2} adds easily to BB than AA. Identify the incorrect statements from the options given below:

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  3. Question 3

    1 Feb 2024

    132
    In the given reactions identify AA and BB.

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  4. Question 4

    23 Jan 2026 S1

    35
    But-2-yne and hydrogen (one mole each) are separately treated with (i) Pd/CPd/C and (ii) Na/Na/ liq. NH3NH_{3} to give the products X and Y respectively. Identify the incorrect statements. (A) XX and YY are stereoisomers. (B) Dipole moment of X is zero (C) Boiling point of X is higher than Y . (D) X and Y react with O3/Zn+H2OO_{3}/Zn + H_{2}O to give different products. Choose the correct answer from the options given below :

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