How the hybridization of c atoms in c-c single bond of HC---C-CH--CH2 is sp3-sp?

Answer 1

The compound HCCCHCH2 contains a triple bond and a double bond. Working along the molecule left to right the hybridisation of the carbon atoms is:-

sp ;sp ; sp2 ; sp2

The formula for a 4 carbon chain containing an sp3 - sp single bond would be

HCCCH2CH3

where the hybridisation left to right is

sp ; sp ; sp3 ; sp3