All India Engineering / Architecture Entrance Examination (AIEEE)
AIEEE 2009 Chemistry
Q. 15. The two functional groups present in a typical carbohydrate are:
Sol.: Carbohydrate is a polyhydroxy aldehyde or polyhydroxy ketone or any compound which give these on hydrolysis. group includes aldehydic as well as ketonic group.
Answer : (4)
Q. 16. Calculate the wavelength (in nanometer) associated with a proton moving at
Q. 17. The bond dissociation energy of B–F in BF3 is 646 kJ mol–1 whereas that of C–F in CF4 is 515 kJ mol–1. The correct reason for higher B–F bond dissociation energy as compared to that of C–F is
Sol: Boron in BF3 has a vacant p–orbital, allowing back bonding while carbon in CF4 has no vacant orbital, so no back bonding is feasible. Thus, B–F bond is stronger than CF4.