In the organic compound `CH_(2) = CH – CH_(2) – CH_(2) – C equivCH`, the pair of hydridised orbitals involved in the formation of: `C_(2) – C_(3)` bond is:
`(a) sp – sp_(2) (b) sp – sp_(3) (c) sp_(2 )– sp_(3) (d) sp_(3) – sp_(3)`

Explanation

When both double bonds are present at equivalent positions, double bond is given preference while numbering the carbon chain. Thus, `underset(sp^(2))overset(1)(C)H_(2) = underset(sp^(2))overset(2)(C)H - underset(sp^(3))overset(3)(C)H_(2)-underset(sp^(3))overset(4)(C)H_(2) - underset(sp)overset(5)(C) -= underset(sp)overset(6)(C)H`
`:. C_(2) - C_(3)` bond is formed by overlap of `sp^(2) - sp^(3)` orbitals.
Thus, option (c) is correct.