Question

Arrange the increasing order of C-C bond length of ethene, ethane and ethyne.

Answer 1

Dear Student,

Bond length are inversely proportional to percentage of s character.

With increase in s character bond length decrease. Hence we calculate the percentage s character in each compound.

Ethyne (H-C≡C-H): here carbon is sp hybridised : % s character = 50 %
Ethene (H₂C=CH₂): here carbon is sp² hybridised : % s character = 33.3 %
Ethane (H₃C-CH₃): here carbon is sp³ hybridised : % s character = 25 %

As order % s character is ethane< ethene < ethyne, so the order of bond length is ethane > ethene > ethyne that is bond length is longest for ethane, smallest for ethyne and intermediate for ethene.

Regards,