The ratio of SP to SP2 carbons HC≡C−CH=CH2 in  is --------------

Double bonded carbon is SP2 hybridized and triple bonded carbon is SP hybridized[Step 2]:HCSP≡CSP−CHSP2=CH2SP2[Step 3]:Number of SP hybridized carbons are two .Number of SP2 hybridized carbons are two[Step 4]:Therefore the ratio of SP carbons to SP2 carbons is 22  i.e one.