Page 280 - Chemistry ICSE Class X

266 ICSE Chemistry – 10
ƒ Pentane (C H ) exhibits the following three structures:
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ƒ Hexane (C H GZJKDKVU VJG HQNNQYKPI ſXG KUQOGTU
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Chain isomers of alkenes
ƒ But-1-ene and 2-methylpropene are chain isomers:

/Ĩ ƚŚĞ ƉŽƐŝƟŽŶ ŶƵŵďĞƌ ŝƐ ϭ͕ ŝƚ ŝƐ
ĐŽŵŵŽŶůLJ ŶŽƚ ŵĞŶƟŽŶĞĚ ŝŶ ƚŚĞ
ĨŽƌŵƵůĂ͘ ,ĞƌĞ͕ ŝƚ ŝƐ ƌĞƚĂŝŶĞĚ ƚŽ ŵĂŬĞ
ƚŚĞ ĐŽŵƉĂƌŝƐŽŶ ďĞƚǁĞĞŶ ƚŚĞ ƚǁŽ Chain isomers of alkynes
ĨŽƌŵƵůĂĞ ĐůĞĂƌĞƌ͘
ƒ Hexyne has the following chain isomers:

(Note that the position of the triple bond remains the same in the carbon chain)

What is the position isomerism
This isomerism arises due to difference in the position of the same
functional group or the same substituent on the chain. The arrangement of
carbon atoms remains the same. For example,
ƒ Chloropropane (C H Cl) can have two position isomers given below:
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ƒ Butene (C H ) can have two position isomers.
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ƒ Butyne (C H ) has the following position isomers:
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