JEE Advanced levelSingle correct optionDifficulty 3 of 3cb104
The correct order of decreasing length of the carbon-carbon single bond in CHX3−CHX3, CHX3−CH=CHX2 and CHX3−C≡CH (bond between the methyl carbon and the next carbon) is
ACHX3−CHX3>CHX3−C≡CH>CHX3−CH=CHX2
BCHX3−CHX3>CHX3−CH=CHX2>CHX3−C≡CH
CCHX3−CH=CHX2>CHX3−CHX3>CHX3−C≡CH
DCHX3−C≡CH>CHX3−CH=CHX2>CHX3−CHX3
Answer: B
The bonds are sp3-sp3 (154 pm), sp3-sp2 (about 150 pm) and sp3-sp (about 146 pm). Greater s-character of the hybrid orbital gives a shorter, stronger bond.