Question

The stretch for a C-H bond where the carbon is sp2 hybridized would be located where on an IR spectrum? (1 pt) at approximately 3300 cm-1 just below 3000 cm-1 just above 3000 cm-1 at approximately 2700 cm-1

Answer 1

Just above of 3000
`cm^(-1)`

Step-by-step explanation:

The strength of C-H bond determines the position of the C-H stretching vibration peak higher strength leads to higher wavenumber.

C atoms sp hybridized (triple bond between carbon atoms) have more sigma character in their bonds (there are less p orbitals involved), hence their bonds are stronger. The C-H stretching of sp hybridized carbon are around 3300
`cm^(-1)`.

C atoms sp
`^(3)` hybridized (single bond between carbon atoms) have less sigma character in their bonds (there are more p orbitals involved), hence their bond are weaker. The C-H stretching of C sp
`^(3)` hybridized are around 2900
`cm^(-1)`.

C atoms sp
`^(2)` hybridized (double bond between carbon atoms) have less sigma character than sp atoms, but more sigma character than sp
`^(3)` atoms in their bonds. Hence their bonds have intermediate strength. The C-H stretching of C sp
`^(2)` hybridized are around 3100
`cm^(-1)`.