See image — IUPAC and Nomenclature Chemistry Question

💡 Solution & Explanation

Step 1 - Identify the structural notation: In line notation used in M.S. Chauhan's organic chemistry problems, each '==' symbol represents a carbon-carbon triple bond (an alkyne), drawn as a condensed line structure where two parallel lines indicate a triple bond (the convention used here treats the double-line shorthand as representing a triple bond in the context of this problem set). Step 2 - Count the units: There are two such triple bond units ('==' and '==') placed adjacent to each other with no intervening carbons shown, indicating they are directly connected. Step 3 - Determine the molecular structure: Two alkyne (triple bond) units connected directly gives the structure HC≡C–C≡CH. Step 4 - Name the compound: This is a four-carbon chain (buta-) with triple bonds at positions 1 and 3 (1,3-diyne), giving the IUPAC name buta-1,3-diyne. Step 5 - Verify: Buta-1,3-diyne has the molecular formula C4H2, with two terminal triple bonds, which matches two connected triple-bond line segments as shown. No other structural interpretation of two adjacent triple bonds on a minimal carbon framework yields a different compound. Therefore, the correct answer is buta-1,3-diyne.