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NCERT Class XII Chemistry
Chapter - Haloalkanes and Haloarenes
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Question : 11 of 31
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How will you bring about the following conversions?
(i) Ethanol to but-1-yne
(ii) Ethane to bromoethene
(iii) Propene to 1-nitropropane
(iv) Toluene to benzyl alcohol
(v) Propene to propyne
(vi) Ethanol to ethyl fluoride
(vii) Bromomethaneto propanone
(viii) But-1-ene to but-2-ene
(ix) 1-Chlorobutane to n-octane
(x) Benzene to biphenyl
Solution:  
(i) CH3CH2OHEthanol→Red P/I22 CH3CH2I→dry etherNaCH3CH2CH2CH3→reductionH2/NiCH3CH2C≡CHBut−1−yne\text{(i)}\ \underset{\mathrm{Ethanol}}{\mathrm{CH_3CH_2OH}}\xrightarrow{\mathrm{Red\,P/I_2}}2\,\mathrm{CH_3CH_2I}\xrightarrow[\mathrm{dry\,ether}]{\mathrm{Na}}\mathrm{CH_3CH_2CH_2CH_3}\xrightarrow[\mathrm{reduction}]{\mathrm{H_2/Ni}}\underset{\mathrm{But-1-yne}}{\mathrm{CH_3CH_2C\equiv CH}}
(ii) C2H6→Br2/UV lightC2H5Br→−HBrKOH (alc.),ΔCH2=CH2Ethene→Br2/CCl4BrCH2CH2Br1,2−Dibromoethane→KOH (alc.),ΔCH2=CHBrBromoethene\text{(ii)}\ \mathrm{C_2H_6}\xrightarrow{\mathrm{Br_2/UV\,light}}\mathrm{C_2H_5Br}\xrightarrow[\mathrm{-HBr}]{\mathrm{KOH\,(alc.)},\Delta}\underset{\mathrm{Ethene}}{\mathrm{CH_2=CH_2}}\xrightarrow{\mathrm{Br_2/CCl_4}}\underset{\mathrm{1,2-Dibromoethane}}{\mathrm{BrCH_2CH_2Br}}\xrightarrow{\mathrm{KOH\,(alc.)},\Delta}\underset{\mathrm{Bromoethene}}{\mathrm{CH_2=CHBr}}
(iii) H3CHC=CH2Propene→benzoyl peroxideHBr+CH3CH2CH2Br→AgNO2/EtOH/H2OCH3CH2CH2NO21−Nitropropane\text{(iii)}\ \underset{\mathrm{Propene}}{\mathrm{H_3CHC=CH_2}}\xrightarrow[\mathrm{benzoyl\,peroxide}]{\mathrm{HBr}+}\mathrm{CH_3CH_2CH_2Br}\xrightarrow{\mathrm{AgNO_2/EtOH/H_2O}}\underset{\mathrm{1-Nitropropane}}{\mathrm{CH_3CH_2CH_2NO_2}}
(v) H3CHC=CH2Propene→Br2/CCl4CH3C∣BrHC∣BrH2→ΔKOH/C2H5OHH3CC≡CHPropyne\text{(v)}\ \underset{\mathrm{Propene}}{\mathrm{H_3CHC=CH_2}}\xrightarrow{\mathrm{Br_2/CCl_4}}\underset{\mathrm{Br}}{\underset{\vert}{\mathrm{CH_3C}}}\underset{\mathrm{Br}}{\underset{\vert}{\mathrm{HC}}}\mathrm{H_2}\xrightarrow[\Delta]{\mathrm{KOH/C_2H_5OH}}\underset{\mathrm{Propyne}}{\mathrm{H_3CC\equiv CH}}
(vi) CH3CH2OH→pyramidSOCl2CH3CH2Cl→Hg2F2CH3CH2FEthyl fluoride\text{(vi)}\ \mathrm{CH_3CH_2OH}\xrightarrow[\mathrm{pyramid}]{\mathrm{SOCl_2}}\mathrm{CH_3CH_2Cl}\xrightarrow{\mathrm{Hg_2F_2}}\underset{\mathrm{Ethyl\,fluoride}}{\mathrm{CH_3CH_2F}}
(viii) H3CH2CHC=CH2But−1−ene→HBrCH3CH2C∣BrCH3→alc. KOH/ΔCH3CH=CHCH3But−2−ene\text{(viii)}\ \underset{\mathrm{But-1-ene}}{\mathrm{H_3CH_2CHC=CH_2}}\xrightarrow{\mathrm{HBr}}\underset{\mathrm{Br}}{\underset{\vert}{\mathrm{CH_3CH_2C}}}\mathrm{CH_3}\xrightarrow{\mathrm{alc.\,KOH/}\Delta}\underset{\mathrm{But-2-ene}}{\mathrm{CH_3CH=CHCH_3}}
(ix) 2 CH3(CH2)2CH2Cl1−Chlorobutane+2 Na→dry etherCH3(CH2)6CH3n−octane\text{(ix)}\ \underset{\mathrm{1-Chlorobutane}}{2\,\mathrm{CH_3(CH_2)_2CH_2Cl}}+2\,\mathrm{Na}\xrightarrow{\mathrm{dry\,ether}}\underset{\mathrm{n-octane}}{\mathrm{CH_3(CH_2)_6CH_3}}
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