If I am given a molecular hydrocarbon structure, how would I be able to tell how sp3 hybridized carbons it possesses?
Like my current question asks How many sp3-hydridized carbon atoms does 11-cis-retinal possess?
Look at the carbon atoms and what is attached to them. If they have a double bond they are sp2 hybridized.
For example,
H3C-CH3(ethane) has two C atoms each with sp3 hybridization.
But H2C=CH2 (ethene)has sp2 hybridization for each C atom.
H3C-CH2=CH2 has the left most C atom with sp3 and the two right most C atoms with sp2.