JEE MainChemistryHydrocarbons
Complete reductive ozonolysis of an acyclic hydrocarbon B yields acetone, glyoxal, and acetaldehyde in a 1:1:1 molar ratio. It is observed that 19.2 mg of B consumes 8.96 mL of H ₂ gas measured at STP ( 1 atm and 273 K ). The number of allylic hydrogen atoms present in the hydrocarbon B is
Correct answer
9
Step-by-step solution
From the ozonolysis products, we can reconstruct the carbon skeleton of the acyclic hydrocarbon B. The products are: Acetone: ( CH ₃)₂ C=O (a terminal fragment) Glyoxal: O=CH - CH=O (a middle fragment) Acetaldehyde: CH ₃- CH=O (a terminal fragment) Connecting the carbonyl carbons by removing oxygen atoms to form double bonds gives the structure of B: ( CH ₃)₂ C=CH - CH=CH - CH ₃ This is 2 -methylhexa- 2,4 -diene. Let us verify with the hydrogenation data: Molecular formula of B is C ₇ H ₁₂ , so its molar mass is 7