A hydrocarbon with 8 σ bonds and 2 π bonds undergoes complete combustion to produce 3 moles of CO₂ per mole of compound.
3 carbons (from 3 CO₂). CH₃C≡CH has 8 σ (6 C-H, 1 C-C, 1 from C≡C) and 2 π (C≡C), and is C₃H₄, producing 3 CO₂ on combustion.
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Isomerism - Stereoisomerism - Geometrical and Optical Isomerism