JEE Main · 2021 · 25 Jul 2021 · Shift 1 · Chapter_pending

The structure is $\mathrm{C}{\mathrm{H}}_3-\mathrm{CH}=\mathrm{CH}-\mathrm{C}\equiv \mathrm{C}-\mathrm{H}$. Every bond between two atoms contains exactly one sigma bond whatever its order, the second and third bonds of a double or triple bond being $\pi$. The chain therefore gives four carbon-carbon sigma bonds, and the hydrogens add six more: three on the methyl carbon, one on each of the two doubly bonded carbons and one on the terminal alkyne carbon. The number of sigma bonds is $10$.