A hydrocarbon C10H16 absorbs 2 mol of H2 over Pt to give C10H20, which absorbs no more H2. The number of rings and the number of pi bonds in the original hydrocarbon are respectively

JEE Advanced levelSingle correct optionDifficulty 3 of 3si092

A hydrocarbon $C X_{10} H X_{16}$ absorbs 2 mol of $H X_{2}$ over Pt to give $C X_{10} H X_{20}$ , which absorbs no more $H X_{2}$ . The number of rings and the number of pi bonds in the original hydrocarbon are respectively

C X_{10} H X_{16}

has degree of unsaturation

(22 - 16) /2 = 3

. Each mole of

H X_{2}

consumed removes one pi bond, so there are 2 pi bonds. The product

C X_{10} H X_{20}

has degree 1, which is one ring that remains. Rings = 3 - 2 = 1.