Alkynes

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Alkynes: Overview

This topic covers concepts such as alkynes, isomerism in alkynes, position isomerism in alkynes, preparation of alkynes, and preparation of alkynes by vicinal dihalides.

Important Questions on Alkynes

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When propyne is treated with aqueous  H 2 S O 4 in presence of  HgS O 4, the major product is:

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The product(s) obtained via hydration (HgSO4+H2SO4) of 1-butyne would be:

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The number of possible structural and configurational isomers of a bromo compound, formed by the addition of 1 mole of HBr to 2-pentyne respectively, are –

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The reagent(s) for the following conversion,

Br-CH2-CH2-Br ? CHCH

is/are

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Which of the following reagents on reaction with acetylene yield same product?

A. O3/H2O+H+                      B. KMNO4/OH-/H2O (cold)

C. SeO2                                       D. O3 + H2O/Zn

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The reagent(s) for the following conversion, 

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Most acidic hydrogen is present in:

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Explain the acidic character of alkyne.

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The product P in the above reaction is

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How many reagents from the list below give effervescence when reacted with 1-pentyne?

NaOH(I), CH3CH2ONa(II), CH3CH2MgBr(III), NaH(IV), NaNH2(V), NaVI, NaHCO3(VII), (CH3)2CH2NLi(VIII), CH3CH2LiIX, C6H5LiX

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The total number structural isomers of alkynes that on catalytic reduction gives 3-ethyl-4-methylheptane are:

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One mole of 1,2-dibromopropane, on treatment with X moles of ,NaNH2 followed by the treatment with ethyl bromide gave a pentyne. The value of X is: 

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An internal alkyne(P) with formula C4H6 reacts with NaNH2 to form a sodium salt of terminal alkyne Q. Q reacts with C2H5Br to form (R). Reaction of R with excess HCl forms S Answer the following questions on the basis of above write up.
The structure of P is

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Complete the following reaction sequence: HCCHLiNH2ACH3CH2ClBHBrC. Comment on the acidic nature of B.

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Acetylene is used in soldering metals and manufacturing synthetic rubber.

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What are the uses of acetylene?

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Catalytic hydrogenation of alkyne in two stages forms _____.

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A product formed by dydrohalogenation of 1,2,- dibromoethane is:

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The isomerism exhibited by alkynes is: