In `CH_(2)=CHCH_(2)CH_(2)C-=CH`, the pair of hybridised orbitals involved in the formation of `C_(2)-C_(3)` bond is:
(1) `sp - sp^(2)`
(2) `sp - sp^(3)`
(3) `sp^(2) - sp^(3)`
(4) `sp^(3) - sp^(3)`

Answer

3

Explanation

When both double and triple bonds are present at equivalent position, tne preference is given to the double bond while numbering the carbon chain. Thus we have,
`underset(sp^(2))overset(1)(CH_(2))=underset(sp^(2))overset(2)(CH)-underset(sp^(3))overset(3)(CH_(2))-underset(sp^(3))overset(4)(CH_(2))-underset(sp)overset(5)(C)-=underset(sp)overset(6)(C)H`
So, `C_(2) - C_(3)` bond is formed by the overlap of `sp^(2) and sp^(3)` - orbitals.