Total number of sigma ($\sigma$) ______ and pi($\pi$) ______ bonds respectively present in hex-1-en-4-yne are :

JEE Main · 2025 · 29 Jan 2025 · Shift 2 · Hydrocarbons

Total number of sigma (

σ

) ______ and pi(

π

) ______ bonds respectively present in hex-1-en-4-yne are :

(A)13 and 3✓ Correct
(B)11 and 3
(C)3 and 13
(D)14 and 3

Answer: (A)

Solution

Hex-1-en-4-yne is

C H_{2} = C H - C H_{2} - C \equiv C - C H_{3}

. Counting sigma bonds: the carbon skeleton contributes 5 C–C sigma bonds (C1–C2, C2–C3, C3–C4, C4–C5, C5–C6), and the hydrogens contribute

2 + 1 + 2 + 0 + 0 + 3 = 8

C–H sigma bonds, for a total of 13 sigma bonds. Counting pi bonds: the C1=C2 double bond supplies 1 pi bond, and the C4≡C5 triple bond supplies 2 pi bonds, for a total of 3 pi bonds. The molecule contains 13 sigma bonds and 3 pi bonds.

JEE Main · 2025 · 29 Jan 2025 · Shift 2 · Single correct option

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